Multimedia applications impose different QoS requirements (e.g., bounded end-to-end delay and jitter) and need an enhanced transport layer protocol that should handle packet loss, minimize errors, manage network congestion, and transmit efficiently. Across an IP network, the transport layer protocol provides data transmission and affects the QoS provided to the application on hand. The most common transport layer protocols used by Internet applications are TCP and UDP. There are also advanced transport layer protocols such as DCCP and TFRC. The authors evaluated the performance of UDP, DCCP, SCTP, and TFRC over wired networks for three traffic flows: data transmission, video streaming, and voice over IP. The evaluation criteria were throughput, end-to-end delay, and packet loss ratio. They compared their performance to learn in which traffic flow/service each of these protocols functions better than the others. The throughput of SCTP and TFRC is better than UDP. DCCP is superior to SCTP and TFRC in terms of end-to-end delay. SCTP is suitable for Internet applications that require high bandwidth.
Four N-substituted citraconisoimides were prepared via dehydration of the corresponding prepared citraconamic acids using N,N\-dicyclohexylcarbodiimide as dehydrating agent. The prepared citraconisoimides were introduced in free radical homopolymerization producing four new poly citraconisoimides. Also the prepared citraconisoimides were introduced in free radical copolymerization with three vinylic monomers including acrylonitrile, methylmethacrylate and methylacrylate producing new copolymers having different physical properties. Moreover two new phenolic resins containing pendent citraconisoimide moiety were prepared via condensation polymerization of N-(hydroxyphenol)citraconisoimide with formaldehyde. The new homopolymers and copoly
... Show MoreThe purified prepared compounds were identified through different methods of identification i.e, I.R, UV-vi^ble-spectroscopy in addition to (coloured tests) Calculation of the sum of OH groups. TLC techniques were also used to test the purity and the speed ofthe rate of flow (RF).
This work concerns the thermal and sound insulation as well as the mechanical properties of polymer matrix composite reinforced with glass fibers. These fibers may have dangerous effect during handling, for example the glass fibers might cause some damage to the eyes, lungs and even skin. For this reason the present work, investigates the behavior of polymer composite reinforced with natural fibers (Plant fibers) as replacement to glass fibers. Unsaturated Polyester resin was used as matrix material reinforced with two types of fibers, one of them is artificial (Glass fibers) and the other type is natural (Jute, Fronds Palm and Reed Fibers) by hand lay-up technique. All fibers are untreated with any chemical solvent. The Percentage of mi
... Show MoreThe shoulder and hip joints though essentially both are ball and socket joints, show structural variability to serve functional needs.
This study aims at revealing some of the structural and functional properties of each of the two joints regarding the factors that contribute to the stability of any joint in the body, namely: bone, ligament, and muscle.
CdSe alloy has been prepared successfully from its high purity elements. Thin films of this alloy with different thicknesses (300,700)nm have been grown on glass substrates at room temperature under very low pressure (10-5)Torr with rate of deposition (1.7)nm/sec by thermal evaporation technique, after that these thin films have been heat treated under low pressure (10-2)Torr at (473,673)K for one hour. X-ray patterns showed that both CdSe alloy and thin films are polycrystalline and have the hexagonal structure with preferential orientation in the [100] and [002] direction respectively. The optical measurements indicated that CdSe thin films have allowed direct optical energy band gap, and it increases from (1.771.84) eV and from (1.6-1
... Show MoreA quantitative interpretation of gravity and magnetic anomalies in west of Tikrit city and surroundings, has been completed utilizing Grav2dc and Mag2dc (2D, 2.5D) forward techniques. The modeling has been carried out along four profiles, two NW-SE profiles along the distinct gravity residual anomalies and two NE-SW profiles along the magnetic residual anomalies. The most geologic plausible model that matches the data was picked. The model along the gravity profile (A-A') reveal faulting of the basement, whereas along the profiles B-B', C-C' and D-D' did not present faulting. The models comprise of two rock units, the first is the sedimentary cover and the second unit i
... Show MoreThe new compounds synthesized by sequence reactions starting from a reaction of 4-hydroxybenzaldehyde with 1,5-dibromo pentane to produce dialdehyde)I(
.Then compound )I( reacted with different aromatic amines to give schiff bases )II-IV(,thereafter added acetyl chloride to schiff bases to yield N-acyl derivatives)V-VII(.While1,3-diazetine derivatives)VIII-X( were synthesized from the reaction of N-acyl derivatives with sodium azide.The reaction of thiourea with N-acyl compounds led to formation of thiourea derivatives (XI-XIII).Finally, the pyrimidine compounds )XIV-XVI( were synthesized by ring closure reaction of compounds(XI-XIII) with diethyl malonate.The synthesized compounds were characterized by measurements of melting points,
The research study included the synthesis of a new series of heterocyclic derivatives containing the antibiotic Levofloxacin. The first way provides for the reaction of Levofloxacin with thionyl chloride in benzene as a solvent to give an acid chloride derivative. A new class of acid hydrazide synthesized from Levofloxacin was studied. Schiff bases were produced via the reaction of acid hydrazide with substituted aromatic ketones in methanol. The next stage involved the response of Schiff bases with thioglycolic acid and mono chloroacetic acid in DMF to produce derivatives of the antibiotic levofloxacin that have five heterocyclic members, including the derivatives thiazolidine-4-one and oxazolidine-5-one. The FTIR, 1HNMR, a
... Show MoreThis study was aimed to determine the impact of Conocarpus erectus L. compost fertilizer, and some micronutrients on growth and production of potato. This research was conducted at one of the fields of the College of Agricultural Engineering Sciences - University of Baghdad. The experiment was implemented using factorial arrangement (4X3X3) within randomized complete block design with three replicates. Conocarpus fertilizer was represented the first factor with three levels (7.5, 15, 30 ton.ha-1), which symbolized (C2, C3, C4). Chemical fertilizer as recommended dose as a control, which symbolized (C1). The second factor was foliar spraying with three levels of iron (0, 100, 200 mg.L-1), which symbolized (F0, F1, F2). The third fact
... Show More