Rational Catalyst Design for Electrochemical Nitrogen Reduction to Ammonia

The Haber-Bosh process is currently potent for ammonia (NH3) production at a high rate but is an energy-intensive process and requires sophisticated infrastructures. Electrochemical nitrogen reduction reaction (NRR) at ambient conditions holds great potential towards sustainable production of NH3. However, this approach is limited by high overpotential, competitive hydrogen evolution reaction (HER), and a low rate of NH3 production. An active, efficient and stable electrocatalyst is required to address these challenges. Advanced strategies for rational catalyst design based on intrinsic and extrinsic catalytic activity are presented in this thesis. These strategies improved the electronic structure, reactants/products interaction on the exposed active sites and better control on the HER that resulted in the enhanced NRR performance. Firstly, synergistic bimetallic CoFe2O4 nanoclusters shows enhanced NRR performance due to the availability of different types of adsorption and active sites for N2 after the incorporation of Co in the Fe3O4 structure. Inspired by the metal–sulfur linkages in the nitrogenase enzyme, a surface modification strategy is then presented to modulate the electronic structure of Ruthenium nanocrystals and improve the N2 availability on a catalytic surface, which suppresses the HER and improves the rate of NH3 production. Similarly, modulated electronic structure of iron by tethering to sulfur in a mesoporous carbon matrix is achieved and confirmed as an efficient NRR catalyst. Theoretical calculations identified enhanced electron transfer and flexible coordination as important features of Fe–S–C linkages responsible for the improved NRR performance. Due to the low solubility of nitrogen in aqueous media and intrinsic competition by HER, very low rates of NH3 production are reported in aqueous electrochemical nitrogen reduction. Moreover, the attribution of measured NH3 as a true product or as an impurity is challenging despite rigorous analytical experimentation. In this regard, the Li-mediated strategy in non-aqueous media is also explored and validated as an efficient NH3 production approach. The role of reaction parameters such as type of electrodes, activation of working electrode, influence of applied current density and voltages. This thesis demonstrates an in-depth insight into rational catalyst design strategies for enhanced NH3 production

Working Capital Management Efficiency and Corporate Governance in Manufacturing Sector of Pakistan

Efficiency in “Working Capital Management” (WCM) has been the key factor of many profitable firms. The purpose of this paper is to examine the impact of characteristics of corporate governance on the WCM efficiency of firms in context of Pakistan. A total of 40 firms listed at Pakistan Stock Exchange (PSX, previously known as Karachi Stock Exchange (KSE)) are selected for the period of 5 years which lead to a total of 200 observations. Cash conversion cycle and current ratio are the main measures of WCM efficiency whereas Chief Executive Officer (CEO) Tenure, CEO Duality, Audit Committee and Board Size are the main measure of corporate governance characteristics. The results state that governance characteristics have significant impact on WCM efficiency. Except CEO Duality, all other independent variables have significant role in explaining WCM efficiency. This paper suggests the management to set policies that favors maintaining the optimal level of working capital. Firms can create value for the shareholders by reducing the investments, however improving efficiency, in working capital. Keeping appropriate size of the board and audit committee, management can improve the WCM efficiency. The findings of this study are also beneficial to investors, company stake holders, and other key intermediaries

Working Capital Management Efficiency and Corporate Governance in Manufacturing Sector of Pakistan

Efficiency in “Working Capital Management” (WCM) has been the key factor of many profitable firms. The purpose of this paper is to examine the impact of characteristics of corporate governance on the WCM efficiency of firms in context of Pakistan. A total of 40 firms listed at Pakistan Stock Exchange (PSX, previously known as Karachi Stock Exchange (KSE)) are selected for the period of 5 years which lead to a total of 200 observations. Cash conversion cycle and current ratio are the main measures of WCM efficiency whereas Chief Executive Officer (CEO) Tenure, CEO Duality, Audit Committee and Board Size are the main measure of corporate governance characteristics. The results state that governance characteristics have significant impact on WCM efficiency. Except CEO Duality, all other independent variables have significant role in explaining WCM efficiency. This paper suggests the management to set policies that favors maintaining the optimal level of working capital. Firms can create value for the shareholders by reducing the investments, however improving efficiency, in working capital. Keeping appropriate size of the board and audit committee, management can improve the WCM efficiency. The findings of this study are also beneficial to investors, company stake holders, and other key intermediaries

Channel clustering and QoS level identification scheme for multi-channel cognitive radio networks

The increasing popularity of wireless services and devices necessitates high bandwidth requirements; however, spectrum resources are not only limited but also heavily underutilized. Multiple license channels that support the same levels of QoS are desirable to resolve the problems posed by the scarcity and inefficient use of spectrum resources in multi-channel cognitive radio networks (MCRNs). One reason is that multimedia services and applications have distinct, stringent QoS requirements. However, due to a lack of coordination between primary and secondary users, identifying the QoS levels supported over available licensed channels has proven to be problematic and has yet to be attempted. This article presents a novel Bayesian non-parametric channel clustering scheme, which identifies the QoS levels supported over available license channels. The proposed scheme employs the infinite Gaussian mixture model and collapsed Gibbs sampler to identify the QoS levels from the feature space of the bit rate, packet delivery ratio, and packet delay variation of licensed channels. Moreover, the real measurements of wireless data traces and comparisons with baseline clustering schemes are used to evaluate the performance of the proposed scheme. © 1979-2012 IEEE. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Muhammad Imran” is provided in this record*

Heterogeneity-aware task allocation in mobile ad hoc cloud

Mobile Ad Hoc Cloud (MAC) enables the use of a multitude of proximate resource-rich mobile devices to provide computational services in the vicinity. However, inattention to mobile device resources and operational heterogeneity-measuring parameters, such as CPU speed, number of cores, and workload, when allocating task in MAC, causes inefficient resource utilization that prolongs task execution time and consumes large amounts of energy. Task execution is remarkably degraded, because the longer execution time and high energy consumption impede the optimum use of MAC. This paper aims to minimize execution time and energy consumption by proposing heterogeneity-aware task allocation solutions for MAC-based compute-intensive tasks. Results of the proposed solutions reveal that incorporation of the heterogeneity-measuring parameters guarantees a shorter execution time and reduces the energy consumption of the compute-intensive tasks in MAC. A system model is developed to validate the proposed solutions' empirical results. In comparison with random-based task allocation, the proposed five solutions based on CPU speed, number of core, workload, CPU speed and workload, and CPU speed, core, and workload reduce execution time up to 56.72%, 53.12%, 56.97%, 61.23%, and 71.55%, respectively. In addition, these heterogeneity-aware task allocation solutions save energy up to 69.78%, 69.06%, 68.25%, 67.26%, and 57.33%, respectively. For this reason, the proposed solutions significantly improve tasks' execution performance, which can increase the optimum use of MAC. © 2013 IEEE

Feasibility of a Solar Thermal Power Plant in Pakistan

Pakistan has been facing an unprecedented energy crisis since the last few years. The problem becomes more severe throughout the year. The current energy shortage crisis has badly hit Pakistan’s economy where hundreds of industries have closed due to lack of electricity to fulfil their requirements. The energy supply and demand gap has risen to 5000 MW [1] and is expected to rise considerably in the coming years as shown in Figure 1. Table 1 shows the existing installed power generation in Pakistan. Pakistan has a huge potential in renewable energy especially solar energy to fill this gap if utilized properly. Pakistan, being in the Sun Belt, is ideally located to take advantage of solar energy technologies. This energy source is widely distributed and abundantly available in the country. Pakistan receives 4.45- 5.83 kWh/m2/day of global horizontal insolation as an annual mean value, with 5.30 kWh/m2/day over most areas of the country [2, 3]. This minimum level of solar radiation (4.45 kWh/m2/day) is higher than the world average of 3.61 kWh/m2/day [4] which shows that Pakistan lies in an excellent solar belt range. Pakistan has six main insolation measuring stations, namely Karachi, Islamabad, Lahore, Quetta, Peshawar and Multan and 37 observatories distributed fairly well over the entire country, recording sunshine hours as shown in Table A in Appendix. From the sunshine hours data it can be seen that most of the cities mentioned receive more than 250 sunshine hours a month. 2006 energy policy has resulted in few practical steps taken for utilizing the abundantly available solar resource in Pakistan. A Solar Water Heating System has installed in a Leather Industry for first time in Pakistan. The system, using 400 m2 Evacuated Collector tubes, provides heated water at 70 to 80 oC (at least 10 degree rise to the incoming water) to the already used boiler system, thus saving 33% of the cost. The Project was funded by Higher Education Commission (HEC) under University-Industry Technological Support Program (UITSP). Solar water heating technology is relatively mature technology in Pakistan but its higher capital cost compared to conventional gas heaters has limited its use so far. This technology is widely recommended by a number of public sector organizations in northern mountains where natural gas is limited and difficult. The solar water heaters are now being commercially produced in the private sector. More than 2000 low cost solar cookers are used in Pakistan for cooking purposes. Similarly, solar dryers are used in Gilgit and Skardu (Northern part of Pakistan) to dry large quantities of fruits such as apricot and transport and sell them later in the urban areas, thus bringing economic prosperity to the area. Fresh water unavailability in large parts of Baluchistan, Sind and southern Punjab is a critical issue. Two solar desalination plants consisting of 240 sills each with a capacity of 6000 gallons of seawater/day have been operational at Gawadar in Baluchistan province. A number of such schemes are under active consideration by local governments in Baluchistan and Thar [5]. The need for constructing solar power plants has been realized both at federal and provincial governments. The government of Sindh recently signed a Memorandum of Understanding with German company Azur Solar for building a 50 MW solar power plant at Dhabeji in District Thatta. The firm Azur Solar will initially set up a 60 kW solar power station to provide free electricity to backward 'goths' (Villages), schools and basic health centres of Badin. Both, technical and economical feasibility of a 50 MW solar thermal power plant using Stirling-Dish (SD) technology in Jacaobabad in Sindh Province of Pakistan is analysed in this chapter. The performance and environmental aspects of Stirling dish for power generation with and without solar energy is examined, discussed and compared. The solar data was collected from Bureau of Meteorology (BoM) of Pakistan and Life cycle cost analysis is performed to determine the economic feasibility of the solar thermal power plant. This study reveals that Jacobabad falls within the high solar energy belt and has minimum radiation energy of 4.45 kWh/m2/day (which is higher than the world average of 3.61 kWh/m2/day) to produce electricity, even during the low sunshine and cloudy days. The study concluded that solar thermal power plant in Pakistan is feasible using solar Stirling dish technology

Radiation pattern synthesis in conformal antenna arrays using modified convex optimization technique

In this paper, a modified convex optimization technique is used for radiationpattern correction in a cylindrical-shaped conformal microstrip array antenna.The technique uses numerical simulations to optimize the amplitude andphase excitations, with the goal to decrease the Euclidean distance betweenthe desired field pattern and the obtained (simulated/measured) field patternwhile maintaining the main beam direction, null's location, and side lobelevels under control. Two prototypes of 1 4 and 2 4 conformal microstripantenna array deformed from linear/planar structure to the prescribed cylin-drical shape, with different radii of curvature, are studied to demonstrate theperformance of the proposed technique. The proposed convex optimizationmodel when applied to conformal antenna array possesses fast computingspeed and high convergence accuracy for radiation pattern synthesis, whichcan be a valuable tool for engineering applications.Dr. Mohammad Alibakhshikenari acknowledges supportfrom the CONEX-Plus programme funded by Universidad Carlos III de Madrid and the European Union's Horizon 2020 research and innovation programme under theMarie Sklodowska-Curie grant agreement No. 801538

Pulmonary placental transmogrification associated with adenocarcinoma of the lung: a case report with a comprehensive review of the literature

Pulmonary placental transmogrification (PT) is a rare entity with less than 40 cases reported in the literature. Most reported cases are associated with either bullous emphysema or with pulmonary fibrochondromatous hamartomas. We present only the second case of PT associated with adenocarcinoma of the lung. A 67-year-old female with multiple chronic medical ailments presented with shortness of breath and was found to have a 6-cm mass in the upper lobe of her right lung. A computed tomography (CT) guided core biopsy was performed that showed a well-differentiated adenocarcinoma. Interestingly the normal lung tissue showed placental villous architecture. A unique feature of our case is that the diagnosis was made on a needle core biopsy, unlike all the other cases in the literature. We also provide a comprehensive review of this rare entit

The GASA Gene Family in Cacao (Theobroma cacao, Malvaceae): Genome Wide Identification and Expression Analysis

The gibberellic acid-stimulated Arabidopsis (GASA/GAST) gene family is widely distributed in plants and involved in various physiological and biological processes. These genes also provide resistance to abiotic and biotic stresses, including antimicrobial, antiviral, and antifungal. We are interested in characterizing the GASA gene family and determining its role in various physiological and biological process in Theobroma cacao. Here, we report 17 tcGASA genes distributed on six chromosomes in T. cacao. The gene structure, promoter region, protein structure and biochemical properties, expression, and phylogenetics of all tcGASAs were analyzed. Phylogenetic analyses divided tcGASA proteins into five groups. Among 17 tcGASA genes, nine segmentally duplicating genes were identified which formed four pairs and cluster together in phylogenetic tree. Differential expression analyses revealed that most of the tcGASA genes showed elevated expression in the seeds (cacao food), implying their role in seed development. The differential expression of tcGASAs was recorded between the tolerant and susceptible cultivars of cacao, which indicating their possible role as fungal resistant. Our findings provide new insight into the function, evolution, and regulatory system of the GASA family genes in T.cacao and may suggest new target genes for development of fungi-resistant cacao varieties in breeding programs