Kinetics of ketone hydrogenation over supported Ru catalysts

A kinetic investigation of the production of y-valerolactone (GVL) via the aqueous phase hydrogenation of levulinic acid (LA) over supported Ru catalysts was carried out, in order to understand how to better design a hydrogenation catalyst for such biomass catalytic strategies. At temperatures representative of biomass processing, the reaction proceeds first through the reduction of the LA ketone group to its corresponding alcohol, 4-hydroxypentanoic acid (HPA), which subsequently produces GVL via intramolecular esterification in solution. The governing kinetics of LA hydrogenation were found to be insensitive to the identity of the support material on which Ru catalysts were prepared. Conversely the stability of supported Ru catalysts in the aqueous phase were strongly dependent on the choice of support, exhibiting severe sintering of Ru nanoparticles, the extent of which appears to be dictated by the bulk electronegative properties of the support material. The presence of a secondary functional group in LA (i.e., a carboxyl group) does not appear to perturb the activity of Ru sites in water, where LA and its mono-functional ketone analog (2-pentanone) hydrogenate at identical rates. LA hydrogenation thus appears kinetically equivalent to that of 2-pentanone. Given the similarity, C3-C5 ketone hydrogenation over Ru/SiO2 in the vapor-phase was examined, alleviating the need to consider solution phase complexities. A single universal microkinetic model for the hydrogenation of ketones over supported Ru catalysts was developed, based on a modified Horiuti-Polanyi-type mechanism involving two distinct surface sites. Through the application of surface lateral interactions to the developed ketone microkinetic model, solvent effects commonly reported for hydrogenations over Ru catalysts are rationalized on the basis of the stabilization of a kinetically relevant transition state

Development of RF Energy Harvesting Technique for Li-Fi Application

Internet has become one of the basic needs for almost everyone in the recent era. It is known that you can connect to the internet via many different ways, such as Local Area Connection (LAN), Wireless Fidelity (Wi-Fi), or using mobile networks (GSM/2G/3G/4G). By the year 2010, scientists have started to develop a new way of broadcasting internet. This way basically depends on emitting data through LEDs. They named it the Light Fidelity (Li-Fi). As a client, you have to connect this light source to your router via LAN or Wi-Fi, and carry it everywhere inside your property. You shall have both light and internet at the same time. While the world is at edge with power consumption, many critics see that Li-Fi is an unnecessary addition to the power consumption, as the device would need to be powered in order to be able to send and receive data. To solve such a problem, as shown in this project, other ambient and renewable energy sources are proposed to be used. Radio Frequency is being harvested and converted into Energy through a small PCB board. Afterwards, the output energy is being used to charge a battery and/or power the LEDs. This will be of great help to reduce the need of the normal electrical system

Dynamic Feedback Flow Control Algorithms for Unicast and Multicast Available Bit Rate Service in Asynchronous Transfer Mode Networks

Asynchronous transfer mode (ATM) network technology has been adopted to integrate different kinds of traffic, like video, audio and data. It provides several service categories including constant bit rate (CBR), variable bit rate (VBR), available bit rate (ABR), and unspecified bit rate (UBR) service. In particular, the ABR service has been approved to use the bandwidth left by CBR and VBR services, which is ideal for data applications and can perform well for real-time applications with the appropriate implementation. Basically ABR servIce attempts to guarantee minimum cell rate, achieve fairness, and minimise cell loss by periodically indicating to sources the rate at which to send. Therefore, there is a critical need for an effective flow control mechanism to allocate network resources (buffers, bandwidth), and provide the negotiated quality of service. This thesis develops dynamic feedback flow control schemes in ATM networks, with primary focus on point-to-point (unicast) and point-tomUltipoint (multicast) ABR algorithms. Firstly, it surveys a number of point-to-point schemes proposed for supporting unicast ABR service. Some of these algorithms do not measure the actual ABR traffic load which leads to either overestimates or underestimates of the bandwidth allocation. Others do not monitor the activity of the sources and overlook the temporarily idle sources. The rest may be implemented with additional complexity. Secondly, the research shifts to the problems of point-to-multipoint algorithms by introducing the basic concept of multicasting ABR servIce and reviewing a group of consolidation schemes, where the compromise between low consolidation nOlse and fast transient response is the main issue. Thirdly, the design and implementation issues have been addressed together with the major drawbacks of the previous schemes and hence two algorithms have been proposed. A dynamic rate-based flow control (DRFC) scheme has been developed to support ABR service in unicast environment, while an adaptive feedback consolidation (AFC) algorithm has been designed for ABR multicasting. Finally, these schemes are extensively tested and compared with others from the literature using a wide range of network configurations and different types of traffic sources. The simulation results show that the DRFC algorithm allocates the available bandwidth fairly among the contending ABR sources, while achieving high link utilisation with reasonable growth of queues. The AFC scheme eliminates the consolidation noise with fast transient response as well as minimising the effect of non-responsive branches

Integration Protocols for Voice and Data Traffic

Increasing demands for multimedia services offer integration of multimedia traffic as a hot issue in the future research areas. As a result, in the literature, many multiplexing schemes have been proposed. However, most of them have been implemented with a high complexity, others may be non-effective to satisfy the multiplexing performance criteria, while the rest are still not subjected to a wide range of analysis. Therefore, there is a critical need for comparing some of the recommended multiplexing schemes as well as developing a simple and effective integration protocol while still achieving reasonable bandwidth utilization. This thesis is intended to examine integration protocols for multimedia traffic, with primary focusing on voice-data integration. Firstly, a survey of the existing multiplexing schemes and related issues are presented. Next, an Adaptive Round Robin (ARR) protocol is proposed, as an alternative for voice-data integration, and extensively simulated. Finally, further comparisons, based on computer simulations, are carried out for various multiplexing schemes including Strictly Priority Servicing (SPS), Fixed Round Robin (FRR), Dynamic Bandwidth Allocation/(T1, T2) and Queue Length Threshold (QLT).As a contribution of the thesis, the proposed protocol tries to avoid the drawbacks of the previous multiplexing schemes besides satisfying the multiplexing performance criteria. The protocol differs from the others in that, it gives a limited priority for voice over data, it organizes the incoming packets to the single First-in First-out (FIFO) output buffer rather than the only outgoing scheduling, i.e., all data sources are polled in order according to the adaptation policy; however, before a data source can send a packet, all active voice sources are polled in order. Thus it provides an improvement in voice delay performance without significant effect on data delay performance over previous protocols. In addition, simulation comparisons between various multiplexing schemes have been discussed. In these simulations voice packets are assumed to be generated from on-off sources (talkspurt-silence calls), which is closer to reality and which is not considered in most of the performance analyses of previous schemes

Trends in Sudanese Cereal Production, Consumption, and Trade

Cereal grains are the most important calorie source in the Sudanese diet. An understanding of cereals in Sudan is important for maintaining efficient and sustainable agricultural and food production. This study analyzes Sudanese cereals by examining trends in cereal production, consumption, and trade during the past four decades and identifies the elements that might affect future production and import demand. The focus is sorghum, wheat, and millet. Data for various years were collected from the production and trade yearbooks of the Food and Agriculture Organization of the United Nations

Short Spinous Process of Cervical Vertebrae in a Sudanese Subject: A Case Report

Introduction: The spinous process is part of the vertebrae and provides muscle attachment for some muscles and ligaments. They are important landmarks and play a role in screw placement during surgical intervention. This report describes a case of a Sudanese with a short cervical spinous process and draws attention to the possibility of anatomical variations in general and the shortage of cervical spinous processes specifically. Case Report: A 70-year-old Sudanese male presented to the emergency department following a road traffic accident. After standard management and patient stabilization, the X-ray showed that the spinous processes of C 3, 4, and 5 cervical vertebrae were short, and those of C 6 and 7 have abnormal anatomy. The inter-spinous distances were well-maintained. The joints and articulations processes of cervical vertebrae were normal without cortication. The patient was stable and admitted for 24 hr for observation and then discharged on analgesics. Conclusion: This is the first case report of the short spinous process among Sudanese. Some of the cervical spinous processes were short, and others had abnormal anatomy. No obvious manifestations were linked to the case. Discussion of anatomical variations should be carried out and implemented with care and in line with the normal and latest developments in biological, anthropology, forensic, and related sciences. Such anatomical abnormality should be considered during radiographing, preparation, and surgical intervention planning. The normal adaption resulting from congenital abnormality or variation can be used as a method for reconstruction surgeries and provides alternatives to clinical management

Biochemical Assessment of Bilirubin Level in Pancreatic Adenocarcinoma Patients in Khartoum State

اﻟﺨﻠﻔﯿﺔ :اﻛﺜﺮ اﻻﻧﻮاع اﻟﻤﻨﺘﺸﺮه ﻟﻤﺮض اﻟﺒﻨﻜﺮﯾﺎس ھﻮ)ﻣﺮض ﺧﺒﯿﺚ ﯾﻨﺸﺄ ﻓﻲ اﻟﻐﺪه( 95% ﻣﻨﮫ ﻋﺒﺎر ه ﻋﻦ ﺳﺮﻃﺎن اﻟﺒﻨﻜﺮﯾﺎس ﯾﻮﺟﺪ ﻓﻲ رأس اﻟﺒﻨﻜﺮﯾﺎس وھﻮ اﻟﻤﺴﺒﺐ اﻟﺮاﺑﻊ ﻣﻦ أﺳﺒﺎب اﻟﻮﻓﺎة ﻓﻲ اﻟﻌﺎﻟﻢ. اﻟﮭﺪف ﻣﻦ اﻟﺪراﺳﮫ ﻗﯿﺎس ﻣﻌﺪل اﻟﻤﺎده اﻟﺼﻔﺮاوﯾﮫ ﻟﻤﺮﯾﺾ ﺳﺮﻃﺎن اﻟﺒﻨﻜﺮﯾﺎس ﻗﺒﻞ وﺑﻌﺪ اﻟﻌﻼج وﻓﻘﺎ ﻟﻠﻌﻤﺮ واﻟﺠﻨﺲ. اﺟﺮﯾﺖ اﻟﺪراﺳﮫ ﻓﻲ ﻣﺮﻛﺰ اﻟﺨﺮﻃﻮم ﻟﻠﻌﻼج ﺑﺎﻷﺷﻌﮫ واﻟﻄﺐ اﻟﻨﻮوي ﻓﻲ اﻟﻔﺘﺮه دﯾﺴﻤﺒﺮ 2017 اﻟﻰ ﺳﺒﺘﻤﺒﺮ 2018. ﺗﻀﻤﻦت اﻟﺪراﺳﮫ ارﺑﻌﮫ وﺛﻤﺎﻧﻮن ﻣﺮﯾﻀﺎ )50رﺟﻼ و34 اﻣﺮاه( ﺗﺘﺮاوح اﻋﻤﺎرھﻢ ﺑﯿﻦ ال20 ﺳﻨﮫ اﻟﻲ70 ﺳﻨﮫ . اﻟﻤﻌﺪل اﻟﻄﺒﯿﻌﻲ ﻟﻠﻤﺎده اﻟﺼﻔﺮاوﯾﮫ اﻟﻜﻠﯿﮫ )اﻟﻰ 1.2 ﻣﻞ/دﺳﻢ( ,اﻟﻤﺎده اﻟﺼﻔﺮاوﯾﮫ اﻟﻤﺒﺎﺷﺮه)اﻟﻰ 0.25ﻣﻞ/دﺳﻢ( واﻟﻤﺎده اﻟﺼﻔﺮاوﯾﮫ اﻟﻐﯿﺮ ﻣﺒﺎﺷﺮه)اﻟﻰ0.95ﻣﻞ/دﺳﻢ(. اﺟﺮﯾﺖ اﻟﺪراﺳﮫ ﻟﺜﻼث ﺳﻨﻮات ﺳﺎﺑﻘﮫ. أﻇﮭﺮت اﻟﺪراسه أن ﻣﻌﺪل اﻟﻤﺎده اﻟﺼﻔﺮاوﯾﮫ اﻟﻜﻠﻲه ﻓﻲ اﻟﻤﺮﺣﻠﮫ اﻷوﻟﻰ ﻗﺒﻞ اﻟﻌﻼج وﺑﻌﺪ اﻟﺠﺮاﺣﮫ وﺑﻌﺪ اﻟﻌﻼج اﻟﻜﯿﻤﺎوي اﻻﺷﻌﺎﻋﻲ ﻛﺎن)1.48±0.49 (9.56±1.48, 2.01±0.77, andﻣﻞﻏﻢ/دﺳﻢ ﻋﻠﻰ اﻟﺘﻮاﻟﻲ. وﻣﻌﺪل اﻟﻤﺎده اﻟﺼﻔﺮاوﯾﮫ اﻟﻤﺒﺎﺷﺮه ﻗﺒﻞ اﻟﻌﻼج وﺑﻌﺪ اﻟﺠﺮاﺣﮫ وﺑﻌﺪ اﻟﻌﻼج اﻟﻜﯿﻤﺎوي اﻻﺷﻌﺎﻋﻲ ﻛﺎن)(5.56±1.40,0.80±0.60, 0.45±,0.38 ﻣﻞﻏﻢ/دﺳﻢ ﻋﻠﻰ اﻟﺘﻮاﻟﻲ. ﻣﻌﺪل اﻟﻤﺎده اﻟﺼﻔﺮاوﯾﮫ اﻟﻐﯿﺮ ﻣﺒﺎﺷﺮه ﻗﺒﻞ اﻟﻌﻼج وﺑﻌﺪ اﻟﺠﺮاﺣﮫ وﺑﻌﺪ اﻟﻌﻼج اﻟﻜﯿﻤﺎوي اﻻﺷﻌﺎﻋﻲ ﻛﺎن)1.02±0.37 ,3.96±1.26,,1.19±0,46(ﻣﻠﻐﻢ /دﺳﻢ ﻋﻠﻰ اﻟﺘﻮاﻟﻲ. أﻇﮭﺮت اﻟﺪراسه ان اﻟﻌﻼج اﻷﻓﻀﻞ ﻟﺨﻔﺾ ﻧﺴﺒﺔ اﻟﻤﺎده اﻟﺼﻔﺮاوﯾﮫ ﻛﺎن اﻟﻌﻼج اﻟﻜﯿﻤﺎوي اﻻﺷﻌﺎﻋﻲ ﻓﻲ اﻟﻤﺮﺣﻠﮫ اﻷوﻟﯿﮫ ﻓﻲ ﻛﻞ اﻟﺜﻼث ﺳﻨﻮات ﻟﻠﻤﺼﺎﺑﯿﻦ

MECHANICAL PROPERTIES OF FIBER REINFORCED POLYMER COMPOSITE – A REVIEW

ABSTRACT. Fiber reinforced plastic composites or as called fiber-reinforced polymer, consists many rewards such as its ultimate strength, its low density, and easier processing procedures. Thus, the fiber-Reinforced polymer is used in many fields for instance: in automotive, constructions, as well as in aerospace. Merging two or more fibers into one mixture polymer matrix guides to develop the hybrid composite. The mechanical properties of single fiber-reinforced polymer composite can be improved by the process of Hybridization. The resin and aggregates can be seen as a polymer concrete composite material signs. The (FRPs) are used instead of the steel in both rehabilitation and construction projects because of their non-corrosive and their light weight Thus they are non-magnetic, inert from the prospective of the chemical composition, also they can be applied easily. In addition, they are suitable economically for strengthening, rehabilitating and seismic retrofit of columns, beams, joints, and many more other uses in structures. In this paper, the mechanical properties of the Fiber-Reinforced Polymer (FRP) is presented in this paper