Showing papers by "Muhammad Younas published in 2016"

Recent Advancements, Fundamental Challenges, and Opportunities in Catalytic Methanation of CO2

Abstract: Commercial and environmental benefits have made carbon dioxide (CO2) methanation one of the topmost research projects all over the world both at the pilot plant and commercial scale. Mitigation of CO2 via carbon capture and storage (CCS) routes have less motivation from a commercial point of view. Therefore, an integrated system is of paramount importance to convert CO2 into value-added products such as methane (CH4) using solar energy (photosynthesis) or surplus electrical energy in hydrolysis for production of reactant hydrogen to use in CO2 methanation. To date, great efforts have been made to investigate both the reaction mechanism and catalysts development for methanation. Here in this review, up to date references have been cited, which are aimed at giving researchers a comprehensive overview of CO2 methanation with respect to the recent advancements in reaction mechanism, catalytic materials, and the novel combination of metal active phase and its synergy. Both thermochemical and electrochemical ro...

Feasibility of CO2 adsorption by solid adsorbents: a review on low-temperature systems

Abstract: In the last few decades of industrialization, the concentration of CO2 in the atmosphere had increased rapidly. Different organizations have invested considerable funds in research activities worldwide for CO2 capture and storage. To date, significant work has been done and various technologies have been proposed for CO2 capture and storage. Both adsorption and absorption are promising techniques for CO2 capture, but low-temperature adsorption processes using solid adsorbents are the prevailing technique nowadays. In this review paper, a variety of adsorbents such as carbonaceous materials, dry alkali metal-based sorbents, zeolites, metal–organic frameworks (MOFs) and microporous organic polymers (MOPs) have been studied. Various methods of chemical or physical modification and the effects of supporting materials have been discussed to enhance CO2 capture capacity of these adsorbents. Low-temperature (<100 °C) adsorption processes for CO2 capture are critically analyzed and concluded on the basis of information available so far in the literature. All the information in CO2 adsorption using different routes has been discussed, summarized and thoroughly presented in this review article. The most important comparative study of relatively new material MOFs and MOPs is carried out between the groups and with other sorbent as well.

Trends and Directions in Cloud Service Selection

Abstract: With the growing popularity of cloud computing the number of cloud service providers and services have significantly increased. Thus selecting the best cloud services becomes a challenging task for prospective cloud users. The process of selecting cloud services involves various factors such as characteristics and models of cloud services, user requirements and knowledge, and service level agreement (SLA), to name a few. This paper investigates into the cloud service selection tools, techniques and models by taking into account the distinguishing characteristics of cloud services. It also reviews and analyses academic research as well as commercial tools in order to identify their strengths and weaknesses in the cloud services selection process. It proposes a framework in order to improve the cloud service selection by taking into account services capabilities, quality attributes, level of user's knowledge and service level agreements. The paper also envisions various directions for future research.

CO2 Adsorption by Modified Palm Shell Activated Carbon (PSAC) Via Chemical and Physical Activation and Metal Impregnation

Abstract: The aim of this study was to verify the ability of nickel-impregnated palm shell activated carbon (PSAC) for CO2 adsorption and compare its performance with the chemically and physically activated PSAC. Sodium hydroxide and CO2 were used as activating agents for chemical and physical activation, respectively. Nickel nitrate hexahydrate (Ni(NO3)2·6H2O) was used as a precursor for metal impregnation. The effect of different chemical loadings (NaOH: 20–50 wt%), metal impregnation (Ni(NO3)2·6H2O: 16–28 wt%), and heat treatment time (1–4 h) was studied as parameters. Adsorption capacity was calculated using breakthrough graphs. The effect of humidity on CO2 adsorption and desorption of CO2 was also investigated in this study. The results revealed that chemically modified PSAC yields the highest adsorption capacity (48.2 mg/g) compared to other methods of activation. Interestingly, it was found that the adsorption capacity of nickel-impregnated PSAC was similar to other types of metal-impregnated activated carb...

A New Model for Testing CRUD Operations in a NoSQL Database

Abstract: NoSQL databases provide high availability and efficiency in data processing but at the expense of weaker consistency. In this paper, we propose a new approach in order to test NoSQL key/value databases in general and their CRUD operations in particular. We design a new context-aware model that takes into account the contextual requirements of clients (users) and the NoSQL database system. Accordingly, we develop a transaction model and testing criteria in order to test NoSQL databases by taking into account transactional and non-transactional CRUD operations. Results from testing criteria are used to analyse the trade-off between availability and consistency of NoSQL databases. In addition, these are used to help NoSQL database users and developers to choose between transactional and non-transactional CRUD operations.

Automating the semantic mapping between regulatory guidelines and organizational processes

Abstract: The mapping of regulatory guidelines with organizational processes is an important aspect of a regulatory-compliance management system. Automating this mapping process can greatly improve the overall compliance process. Currently, there is research on mapping between different entities such as ontology mapping, sentence similarity, semantic similarity and regulation-requirement mapping. However, there has not been adequate research on the automation of the mapping process between regulatory guidelines and organizational processes. In this paper, we explain how Natural Language Processing and Semantic Web technologies can be applied in this area. In particular, we explain how we can take advantage of the structures of regulation-ontology and the process-ontology in order to compute the similarity between a regulatory guideline and a process. Our methodology is validated using a case study in the Pharmaceutical industry, which has shown promising results.

Evaluation of a channel assignment scheme in mobile network systems

Abstract: The channel assignment problem is a complex problem which requires that under certain constraints a minimum number of channels have to be assigned to mobile calls in the wireless mobile system. In this paper, we propose a new scheme, which is based on double band frequency and channel borrowing strategy. The proposed scheme takes into account factors such as limited bandwidth of wireless networks and the capacity of underlying servers involved in processing mobile calls. It aims to ensure end-to-end performance by considering the characteristics of mobile devices. This is achieved by determining the position of users (or mobile stations) in wireless mobile systems. The proposed scheme is simulated in order to investigate its efficiency within a specific area of a large city in Saudi Arabia. Experimental results demonstrate that the proposed scheme significantly improves the performance of mobile calls as well as reduces the blocking when the number of mobile call increases.

A Multi-key Transactions Model for NoSQL Cloud Database Systems

Abstract: NoSQL cloud database systems are new types of databases that are built across thousands of cloud nodes and are capable of storing and processing Big Data. NoSQL systems have increasingly been used in large scale applications that need high availability and efficiency but with weaker consistency. Consequently, such systems lack support for standard transactions which provide stronger consistency. This paper proposes a new multi-key transactional model which provides NoSQL systems with standard transaction support and stronger level of data consistency. The strategy is to supplement current NoSQL architecture with an extra layer that manages transactions. The proposed model is configurable where consistency, availability and efficiency can be adjusted based on application requirements. The proposed model is validated through a prototype system using MongoDB. Preliminary experiments show that it ensures stronger consistency and maintains good performance.

Bioelectrochemical system for landfill leachate treatment – challenges, opportunities, and recommendations

Abstract: Increasing awareness of the energy–environment centers leads to the development of new technologies that have a direct impact on energy production and consumption during environmental remediation. Bioelectrochemical system (BES) is anticipated to be the emerging technology for the simultaneous removal/recovery of resources such as energy, nutrients, water, and heavy metals. Organic compounds inside the leachate are oxidized by micro-organisms which in turn lead to the production of energy and other value-added resources. Through the integration of membrane process such as forward osmosis in BES will help to recover the high-quality water for applications like agricultural. Recovery of metals is largely affected by uncertainty in concentration but still recovery of metal is achievable in leachate. Phosphorous and ammonia can be recovered through cathode reduction reactions driven by electricity generation. Low bioavailability of landfill leachate is one of the major challenges for BES which can be ...

Defects in zinc oxide grown by pulsed laser deposition

Abstract: ZnO films are grown on c-plane sapphire using the pulsed laser deposition method. Systematic studies on the effects of annealing are performed to understand the thermal evolutions of the defects in the films. Particular attention is paid to the discussions of the ZnO/sapphire interface thermal stability, the Zn-vacancy related defects having different microstructures, the origins of the green luminescence (∼2.4–2.5 eV) and the near band edge (NBE) emission at 3.23 eV.

Current scenario and threats to Ichthyo-diversity in the foothills of Hindu Kush: addition to the checklist of coldwater fishes of Pakistan.

Abstract: Chitral, the pinnacle of Hindu Kush, draining 31 notable glaciers, is least studied for Ichthyo-faunal diversity. This work explored the fish fauna and the risk factors for the Ichthyo-faunal diversity loss at the foothills of Hindu Kush. A total of 21 fish species were collected from different parts and tributaries of River Chitral, from Shandur up to Arandu, extending to Afghanistan border. Our collection reported 4 fish species for the first time from Pakistan, namely Acanthocobitis uropthalmus, Lepidopygnosis typus, Horalabiosa palaniensis, Horalabiosa joshuai. One species namely Nangra robusta is reported for the first time from River Chitral. Alluvial nature of rocks, construction of hydro projects and duck ponds, introduction of exotic species, erosion and sedimentation of rivers and streams, illegal fishing, and effluent discharges are the major concerns. Major threats to biodiversity loss need to be addressed for proper conservation of biodiversity as a whole and Ichthyo-diversity in particular. A minimum of 193 freshwater species represent the freshwater fauna of Pakistan. These species belong to class Actinopterygii, sub class Teleostei, 3 cohorts, 6 superorders, 13 orders, 30 families and 86 genera (Rafique, 2007; Rafique and Khan, 2012). This variety is contributed by both the exotic and native species of Pakistan; however a high proportion is of endemic species, belonging to three genera (Triplophysa, Schistura and Glyptothorax), have low agility restricted to their native river systems. Their cold water nature keeps them confined to the hilly streams, isolated from other cold water and warm water species. Their cold water habitat provides distinct adaptations and evolution. The history of these fish species can be traced back to the uplift to Himalayas, Hindukush and Karakoram ranges, because of which the ancestors of these fishes had to face hard conditions of snow cold and fast running water (Jayaram, 1982). Most of the endemic fish species of Pakistan are restricted to mountainous and submountainous areas. The damming importance of this region is a serious threat to the extinction of some of the important freshwater Ichthyo-diversity (Regnier et al., 2009). Around 20% of the world’s freshwater fish is currently either endangered or extinct (Ali et al., 2010). The Northern landscape of Pakistan is covered by high mountains, and serves as a perennial source of __________________________________ * Corresponding author arifjan@sbbu.edu.pk 0030-9923/2016/0001-0285 $ 8.00/0 Copyright 2016 Zoological Society of Pakistan freshwater. Here in this region three ranges the Himalayas, Hindu Kush and Karakoram extend from east to west. Water of this region and of western low mountains are classified as cold water and its Ichthyofauna as cold water fishes of both native and exotic nature. Coldwater fishes are restricted only to this part of the country (Petr, 1999). The main objective of the study was to examine the Ichthyo-diversity and to identify the causes and threats of its loss, in the vicinity of the Himalayas, which is a worldwide focused point in terms of biodiversity. Chitral is bestowed with a vast variety of aquatic resources because of the presence of Hindu Kush (a sub range of Himalaya) in its vicinity. About 31 prominent glaciers serves as permanent sources of streams and small rivers, which finally act as tributaries to river Chitral. The presence of cold water habitat is ideal for preserving and the evolution of freshwater fauna of Chital (IUCN, 2009). Materials and methods Fish samples were collected from different localities of district Chitral including the remote areas, e.g. Yar Khoon lasht, Sor laspur, Mastuj and Booni upto Arandu. Fishes were fixed in 10% formalin solution immediately after its collection and were shifted to 70% alcohol later on in the laboratory of the Department of Zoology, Shaheed Benazir Bhutto University, Chitral Campus. The fishes were identified using the following standard fish identification keys: Jayaram (1999), Talwar and Jhingran (1991), Mirza and Sandhu (2007), Nelson Article Information Received 16 January 2015 Revised 9 August 2015 Accepted 19 September 2015 Available online 1 January 2016 Authors’ Contributions AJ has conducted the field work, analyzed the data and wrote the article. HS, H and IA helped in the field work arrangements. MY, RU and IU helped in literature search. AR helped in identification.

Sensors in your Clothes: Design and Development of a Prototype

Abstract: Wearable computing is fast advancing as a preferred approach for integrating software solutions not only in our environment, but also in our everyday garments to exploit the numerous information sources we constantly interact with. This paper explores this context further by showing the possible use of wearable sensor technology for information critical information systems, through the design and development of a proof-of-concept prototype.