Increased Emulsion Stability for Reverse Y‐Shaped Sugar‐Based Surfactants

A series of reverse Y‐shaped surfactants containing aromatic and aliphatic linkers to combine two short hydrocarbon chains and one carbohydrate head group was prepared. Liquid crystalline behavior, air–water interfacial properties, and efficiency as an emulsifier was investigated for each reverse Y‐shaped surfactant. All reverse Y‐shaped surfactants mediated higher emulsion stabilities for water‐in‐oil compared to common typical reference surfactants, reflecting an improved ability to cope with a curvature towards water. The introduction of a benzene ring into the linker substantially increased the affinity of the surfactant for hydrophobic media, resulting in improved emulsion stability for both water‐in‐oil and oil‐in‐water.     

Influence of Hydrogen Bonding on Low Critical Micellar Concentration Value and Formation of Giant Vesicle of Triazole-Contained Amphiphile

An amphiphile molecule consisting of triazole moiety has been thoroughly investigated using different approaches in its aqueous condition. The studies have discovered the explicit function of its heteroaromatic ability in molecular self-assembling. From the fluorescence evidence, the triazole-based amphiphile has shown that the aggregation-induced emission behavior is mainly due to the triazolyl. It suggests that the triazole is directly involved in the self-assembling mechanism through an intermolecular interaction. This interaction can be verified by the shifting of proton frequency of the triazole, which is clearly shown by the constant frequency of the proton above the critical micellar concentration (CMC) value. The frequency suggests the establishing hydrogen bond that occurred between the hydrogen and the second nitrogen of the adjacent triazole. These results are consistent with the micellization of the molecule which was determined at a very low CMC value (0.1 mM). The absorbance and optical polarizing microscopy results also support the evidence of the growth of giant vesicles produced from the neutralization of the amphiphile. The formation of stable giant vesicles at neutral pH demonstrates the immediate strong hydrogen bonding connections within the triazoles layer in the bilayer. The discovery reveals that internal hydrogen bonds formed from a heteroaromatic with the appropriate molecular arrangement can promote self-aggregation and enhance overall stability.     

BER estimation of optical WDM RZ-DPSK systems through the differential phase Q

The optical return-to-zero differential phase-shift keying system is analyzed to determine the accuracy of the differential phase Q method in estimating the bit-error rate (BER). It is found that it consistently underestimates the BER though it successfully predicts the qualitative behavior of single-channel and wavelength-division-multiplexed systems for back-to-back and point-to-point configurations. A simple modification reduced the underestimation and produced accurate results.     

Software SMEs’ unofficial readiness for CMMI<Superscript>®</Superscript>-based software process improvement

The goal of software process improvement (SPI) is to improve software processes and produce high-quality software, but the results of SPI efforts in small- and medium-sized enterprises (SMEs) that develop software have been unsatisfactory. The objective of this study is to support the prolific and successful CMMI-based implementation of SPI in SMEs by presenting the facts related to the unofficial adoption of CMMI level 2 process area-specific practices by software SMEs. Two questionnaire surveys were performed, and 42 questionnaires were selected for data analysis. The questionnaires were filled out by experts from 42 non-CMMI-certified software SMEs based in Malaysia and Pakistan. In the case of each process area of CMMI level 2, the respondents were asked to choose from three categories, namely ‘below 50 %,’ ‘50–75 %,’ and ‘above 75 %’. The percentages indicated the extent to which process area-specific practices are routinely followed in the respondents’ respective organizations. To deal with differing standards for defining SMEs, the notion of the common range standard has been introduced. The results of the study show that a large segment of software development SMEs informally follows the specific practices of CMMI level 2 process areas and thus has true potential for rapid and effective CMMI-based SPI. The results further indicate that, in the case of four process areas of CMMI level 2, there are statistically significant differences between the readiness of small and medium software enterprises to adopt the specific practices of those process areas, and between trends on their part to do so unofficially. The findings, manifesting various degrees of unofficial readiness for CMMI-based SPI among SMEs, can be used to define criteria for the selection of SMEs that would be included in SPI initiatives funded by relevant authorities. In the interests of developing fruitful CMMI-based SPI and to enhance the success rate of CMMI-based SPI initiatives, the study suggests that ‘ready’ or ‘potential’ SMEs should be given priority for SPI initiatives.     

Nonlinear BER performance of dense optical WDM manhattan street network with deflection routing

The nonlinear bit-error-rate (BER) performance of dense optical wavelength-division-multiplexed (WDM) Manhattan Street Networks with deflection routing was evaluated using an extendable semianalytical process. The results show that nonlinear effects impose significant performance penalties on dense WDM networks, both in terms of maximum hops attainable and average BER, and should be taken into account when modeling such networks. Simple techniques such as optimal amplifier positioning can reduce the nonlinear penalties.     

Effect of Alkalization on Mechanical Properties of Water Hyacinth Fibers-Unsaturated Polyester Composites

Characteristic of local water hyacinth (WH) fibers and composites that consist of mixing WH fibers and unsaturated polyester (UPR) were studied. Composites mixed with the WH fibers treated in different alkali concentration for 1 h soaking time were tested by tensile and flexure machine and their fracture surface was observed by using scanning electron microscope (SEM). The results show that 7% NaOH, 1 h, treated WH fibers provided better mechanical properties on UPR matrix composites in comparison with other alkali concentrations. From SEM observation, some untreated WH fibers pulled out from their matrix were observed clearly in fracture surface of composites. The high alkali concentration created damage of cellulosic structure, thus decreasing of mechanical properties of the composites.     

Alkali Treatment of Screw Pine (Pandanus Odoratissimus) Fibers and Its Effect on Unsaturated Polyester Composites

Characteristics of Screw Pine fiber of species Pandanus Odoratissimus (PO fibers) and short PO fibers reinforced composite were studied. The results show that various alkali concentrations changed ability of PO fibers in absorptions of moisture, chemical compositions and cross-sectional area. The untreated and treated PO fibers were compounded with unsaturated polyester to evaluate their mechanical properties. The treated PO fiber composites exhibit high mechanical properties in comparison with untreated ones. SEM photographs revealed a different fracture surface between untreated PO fiber-reinforced composites and treated ones.     

Packet based echo cancellation for VoIP networks

In today’s modern telephony network, VoIP is fast emerging as one of the main communication techniques. However, the performance and the quality of VoIP are affected by echo. Packet Based Echo Canceller (PBEC) is introduced, as a solution to cancel echo in the VoIP network. PBEC can replace the current echo cancellers, which are located in the Public Switched Telephony Network (PSTN) central switches. The operating principle of the PBEC is explained and its advantages are highlighted. The performance of the PBEC using different speech codecs is also studied. Using the PBEC, a maximum Echo Return Loss Enhancement (ERLE) of 37.39 dB has been achieved when used with the Pulse Code Modulation (PCM) based speech codec. From the simulation results, it can be seen that the performance of the Adaptive Differential Pulse Code Modulation (ADPCM) clearly matches the performance of the PCM based speech codec. The other major problem affecting the VoIP network is the issue of packet loss. This issue of packet loss has been successfully addressed in this paper by the insertion of random values. With the insertion of random values, the ERLE increases by 4.81 dB compared to when there is no insertion of random value. The PBEC with the utilization of random values would make the VoIP a better communication tool.     

Amide-Based Surfactants from Methyl Glucoside as Potential Emulsifiers

A series of amide-linked surfactants from methyl glucoside was synthesized and investigated for their potential use as water-in-oil emulsifiers. The synthetic concept combined a nucleophilic substitution approach with a Staudinger coupling of the intermediate azide. Both straight and Guerbet-type branched fatty acids ranging from C₈ to C₁₆ were applied. All surfactants exhibited very high Krafft temperatures, which were related to the amide linkage and exclusively formed the hexagonal H₁-phase. The Guerbet C₁₆ surfactant enabled the formation of a stable water-in-oil gel at ambient temperature, which, however, required heating to form the corresponding fluid emulsion.