Variable-Length Subnet Masks (VLSM), often referred to as "subnetting a subnet", is used to maximize addressing efficiency. The network administrator is able to use a long mask on networks with few hosts, and a short mask on subnets with many hosts. This addressing scheme allows growth and does not involve wasting addresses. VLSM gives a way of subnetting a network with
minimal loses of IP addresses for a specific range. Unfortunately, the network administrator has to perform several mathematical steps (or use charts) to get the required results from VLSM. In this paper, a simple graph simulator is proposed (using Visual Basic 6.0 Language) to perform all the required mathematical steps and to display the obtained required informatio

The reaction of(2-oxo-2H-chromen-3-Carbonyl chloride)(k1) with hydrazine in boiling ethanol gives the hydrazide(K2).When compound (k2) reacts with various aromatic aldehydes ,the corres ponding Schiff bases(k3–k4) achieve new series of thiazotidines (k5–k6) and azetidinones (k7–k8) obtained from the reactions of appropriate Schiff bases with mercapto acetic acid and chloro acetyl chloride respectively. All the compounds are characterized by FT-IR,1H-NMR and GC-Ms.

Worldwide attention is being focused on  nanocrystalline  zeolites  and they are replacing conventional ones due to their pronounced potential in many fields. In this study, NaY zeolite has been prepared hydrothermally using sol –gel method and modified to the proton type by ion –exchange process. Characterization is made using X-ray diffraction (XRD), thermogravimetric analysis (TGA),  Fourier transform infrared spectroscopy (FTIR),  Atomic force microscopy (AFM), Brunauer –Emmet- Teller (BET) nitrogen adsorption method, Ammonia Temperature programmed desorption (NH₃-TPD) and Scanning electron microscopy( SEM).  The effect of aging time, silica to alumina ratio is studied and the results sh

           This thesis study (pen weight and diversity of Arabic calligraphy), including the Arabic script went through multiple bodies, it came through the natural evolution of societies, and helped in the renovation and development of calligraphy after they gained a clear identity as a result of development that has occurred in the materials and writing instruments, especially industry pen that led to the diversity of Arabic calligraphy, and through the exploratory research and modeling study, which was obtained that the researcher could pose a problem discussed in the first chapter of his study follows by asking: is the pen is the weight of the role in the diversity of Arabic calligrap

Many of the signs that the global energy system indicate the start of a period of transition from total dependence on fossil energy sources, especially oil, into a new era in which alternative energy sources play an important role in meeting the growing needs of energy demand, so sought many of the developed countries through research the studies carried out to try to bring renewable energy sources and non-renewable (shale oil, oil sands, solar energy, wind energy .... etc) replace traditional fossil energy sources (oil, gas, coal) and despite the recent availability dramatically and spread throughout the the world, but they are going to dry up in the foreseeable future. So many countries, especially the developed sought to find

This study is conducted to carry out a straightforward way appropriate for quality monitoring and stability of arc stud welding process, followed by a number of procedures to control the quality of welded samples, namely torque destructive testing and visual inspection context.  Those procedures were being performed to support the monitoring system and verify its validity. Thus, continuous on-line monitoring guarantees earlier discovering stud welding defects and avoiding weld repeatability. On-line welding electronic monitoring system is for non destructive determining if a just completed weld is satisfactory or unsatisfactory, depending on welding current peak value detected by the system. Also, it has been observed significant ha

In the present paper we report the synthesis of a new ligand [HL][(2-1-[(2-hydroxy-benzylidene)-hydrazono]-ethyl) benzene-1, 3, 5-triol and its complexes with (Mn", Fe", Cd", and Hg") The ligand was prepared in two steps. In the first step a solution of salicylaldehyed in methanol reacted under reflux with hydrazinemonohydrate to give an intermediate compound which reacted in the second step with 2, 4, 6-trihydroxidernonohydrate giving the tientioned ligand. The complexes were synthesis by direct reaction of the corresponding metal chloride with ligand. The ligand and the complexes have been characterized by spectroscopic methods [" H NMR, IR, UV-Vis,, atomic absorption], HPLC microanalysis along with conductivity measurements. From the abo

In contrast to the classical antibacterial sulfa drugs that are unsubstituted or monosubstituted, our newly synthesized analogs were designed to obtain sulfonamide moiety containing disubstituted hetero nitrogen atom. These compounds were formed successfully by chlorosulfonation of acetanilide and the product was treated with different cyclic amines and finally amide hydrolysis was necessary to get agents that were analyzed for IR, UV, CHN, melting points and solubility. At last, we studied their antibacterial activity on certain types of bacteria and we noticed the inactivity due to possible steric factor. Principly, this means these products have no inhibiting action against the used microbes.