There are many studies dealt with handoff management in mobile communication systems and some of these studies presented handoff schemes to manage this important process in cellular network. All previous schemes used relative signal strength (RSS) measurements. In this work, a new proposed handoff scheme had been presented depending not only on the RSS measurements but also used the threshold distance and neighboring BSS power margins in order to improve the handoff management process. We submitted here a threshold RSS as a condition to make a handoff when a mobile station moves from one cell to another this at first, then we submitted also a specified margin between the current received signal and the ongoing BS's received signal must be satisfied in order to transfer opening call within new cell, finally we submitted again a threshold distance to exceed by a mobile station in order handoff process is done. The purpose of all these thresholds is to decrease the unnecessary handoffs that can be happened and causing either handoff delayed or call dropped. Our simulation results illustrated that the new proposed scheme is sufficiently improved the handoff process with reducing the unnecessary handoffs as compared with other schemes.
Propranolol is a nonselective-adrenergic blocker used in the treatment of hypertension, cardiac arrhythmias, and angina pectoris. A significant problem in propranolol therapy is that it undergoes extensive presystemic metabolism after oral administration leading to reduced bioavailability. In this study, two new propranolol derivatives have been designed, synthesized and characterized. These compounds were formed by acylation of propranolol followed by nucleophilic substitution reaction of acylated propranolol, these derivatives were analyzed for IR, CHN, melting points, and evaluated for their lipophilic properties compared with propranolol. The lower partition coefficient of these two derivatives revealed that the prodrug approach may be
... Show MoreAdvanced drug delivery systems offer undeniable benefits for drug delivery. In the past three decades, new methods have been proposed to develop a novel carriers for drug delivery. Nowadays, the major goal is to maximize therapeutic benefit while minimizing side effects. Drug delivery technique is clearly shifting from the micro to nanoscale. Nano-drug delivery systems (NDDSs) are the most promising approach utilized to improve the accuracy of drug delivery and the efficacy of drugs.In this narrative review article, we evaluate how delivery challenges associated with commercial marketed products and discuss newer DDS is being carried out to overcome these challenges .Different colloidal carrier systems such as carbon nanotube ,li
... Show MoreThis work contain many steps starting from esterification of isophthalic acid to yield diester compound [I] which was converted to their acid hydrazide [II], then the later compound reacted with ethylacetoacetate to yield pyrazol-5-one compound [III]. Afterword added acetyl chloride to give the compound [IV], thereaction of this compound with theiosemicarbazide ledto produce a new carbothioamide compound [V], Which was reacted with ethyl chloro acetate to yield thethioxoimidazolidin compound [VI]. The condensation reaction of this compound with different substituted aldehyde give new alkene derivatives[VII]a-d. The synthesized compounds were characterized by melting points , FT-IR ,1H-NMR and Mass spectroscopy .
In the present study, new five polymers of acryloyl chloride have been synthesized by reaction 4-aminoantipyrine with many substituted acid chloride (A-E). Then condensation of polyacryloyl chloride with the product in one step (A-E), in a suitable solvent in the presence amount of (Et3N) to obtain new polyimides(A1-E5). The prepared compounds were characterized by UV. FT-IR, 1H-NMR and 13C-NMR spectroscopy and measuring of other physical properties such as softening point, melting point and solublities.
This paper aims to introduce certain new kinds of ideals on pseudo-BG-Algebra (P-BG-A), such as pseudo-closed ideal (P-CI), pseudo-completely closed ideal (P-CCI), and pseudo-n-ideal (P-n-I). Firstly, a (P-n-I) is defined and its pertinent properties are explored. Some important properties have been proven, for example, any pseudo-ideal is a (P-n-I), but the opposite is not generally true, an example was given of the opposite direction. Also, every pseudo-subalgebra of a (P-BG-A) is a pseudo ideal and it is a (P-n-I). Secondly, (P-CI) and a (P-CCI) ideal are defined. After that, we prove that every pseudo-subalgebra of a (P-BG-A) is a (P-CI) and the converse is true. The relationship between (P-BG-A) and pseudo-BH-algebra is demonstrated un
... Show MoreNovel heterocyclic polyimide 5(a,b) have been synthesized based on polyacrylic backbone. The synthetic route start with nucleophilic substitution of 2-amino, or 4-amino, pyridine 1(a,b) to the polyacryloyl chloride afforded poly substituted amide 2(a,b). Another nucleophilic substitution were carried with adipoyl chloride to form polyimide chloride 3(a,b). Treatment of 3(a,b) with hydrazine hydrate afforded acid hydrazide polyimide 4(a,b), which upon cyclocondensation with carbon disulfide gave the target heterocyclic polyimide. The synthesized compounds were identified by spectroscopic methods: FT-IR, 1H-NMR and 13C-NMR.
A research include of synthesized five member ring, which has been synthesized by condensation of 2-(1-(4- hydroxyphenyl) ethylidene)hydrazine-1-carbothioamide[I] with α-chloro ethylacetate in sodium acetate (fused) to form ethyl 2-(4-(1-((4-oxo-2-thioxopyrrolidin-3-ylidene)hydrazono) ethyl)phenoxy)acetate [II]. After that reacted [II]with hydrazine hydrate to resulting compound [III]. Compound [III] was refluxed with 4-aminobenzoicacid in excess of phosphorus oxy chloride give compound [IV],the later compound [IV] interact with acetyl acetone or ethylacetoacetate give to pyrazole and pyrazoline derivatives[V],[VI]. While when reacted with different aromatic aldehydes and one ketone consistence Schiff base derivatives [VII]a-e . The FTIR a
... Show MoreIn this paper the new starting material 2-(5-chloro-1H-benzo[d]imidazole-2-yl) aniline (1) was synthesized by the condensation reaction of 4-chloro-o-phenylenediamine and anthranilic acid .The new Mannich base derivatives were synthesized using formaldehyde and different secondary amines to synthesize a new set of benzimidazole derivatives(2-5). Also, the new Schiff-base derivatives (6-10) were synthesized from the reaction of compound (1) with various aromatic aldehydes and the closure-ring was done successfully using mercapto acetic acid to get the new thiazolidine derivatives(11-12).These new compounds were characterized using some physical techniques like:FT-IR Spectra and 1HNMR Spectra.
The technological development in the field of information and communication has been accompanied by the emergence of security challenges related to the transmission of information. Encryption is a good solution. An encryption process is one of the traditional methods to protect the plain text, by converting it into inarticulate form. Encryption implemented can be occurred by using some substitute techniques, shifting techniques, or mathematical operations. This paper proposed a method with two branches to encrypt text. The first branch is a new mathematical model to create and exchange keys, the proposed key exchange method is the development of Diffie-Hellman. It is a new mathematical operations model to exchange keys based on prime num
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