(R, S) conjugate solution to coupled Sylvester complex matrix equations with conjugate of two unknowns

In this work, we are concerned with (R, S) – conjugate solutions to coupled Sylvester complex matrix equations with conjugate of two unknowns. When the considered two matrix equations are consistent, it is demonstrated that the solutions can be obtained by utilizing this iterative algorithm for any initial arbitrary (R,S) – conjugate matrices V1,W1. A necessary and sufficient condition is established to guarantee that the proposed method converges to the (R,S) – conjugate solutions. Finally, two numerical examples are provided to demonstrate the efficiency of the described iterative technique

Punching Capacity of UHPC Post Tensioned Flat Slabs with and Without Shear Reinforcement: An Experimental Study

Punching capacity is one of the main items in the design of both pre-stressed and non-pre-stressed flat slabs. All international design codes include provisions to prevent this type of failure. Unfortunately, there is no code provision for UHPC yet, and hence, the aim of this research is to experimentally investigate the impact of column dimensions and punching reinforcement on the punching capacity of post-tensioned slabs and compare the results with the international design codes’ provisions to evaluate its validity. The test program included five slabs with a compressive strength of 120 MPa: one as a control sample, two to study the effect of column size, and the last two to study the effect of punching reinforcement. Comparing the results with the design codes showed that ACI-318 is more accurate with an average deviation of about 5%, while EC2 is more conservative with an average deviation of about 20%. Besides that, punching reinforcement reduces the size of the punching wedge by increasing the crack angle to 28° instead of 22° for slabs without punching reinforcement. Also, the results assure that both ductility and stiffness are enhanced with the increased column dimensions and punching reinforcement ratio. Doi: 10.28991/CEJ-2023-09-03-06 Full Text: PD

Removing of heavymetals from water by chitosan nanoparticles

Chitosan was prepared by deacetylation of chitin. The prepared chitosan has characterized bymolecular weight, degree of deacetylation, and ash %. Chitosan nanoparticles were prepared byionotropic gelation of chitosan with tripolyphosphate anions. The structure and particle size of chitosan nanoparticles have confirmed via FTIR analysis and TEM imaging.The chitosan nanoparticles were used in water treatment to remove metal ions from sample contains 20 ppm from each Fe+2, Mn+2, Zn+2 and Cu+2.The optimum conditions for this study were at 2 g/l of chitosan nanoparticles, pH 7 and 30 min of mixing time. Chitosan showed the highest performance under these conditions with removing percent 99.94% 80.85% 90.49% and 95.93% from Fe+2, Mn+2, Zn+2 and Cu+2 respectively

Removing of heavymetals from water by chitosan nanoparticles

Chitosan was prepared by deacetylation of chitin. The prepared chitosan has characterized bymolecular weight, degree of deacetylation, and ash %. Chitosan nanoparticles were prepared byionotropic gelation of chitosan with tripolyphosphate anions. The structure and particle size of chitosan nanoparticles have confirmed via FTIR analysis and TEM imaging.The chitosan nanoparticles were used in water treatment to remove metal ions from sample contains 20 ppm from each Fe+2, Mn+2, Zn+2 and Cu+2.The optimum conditions for this study were at 2 g/l of chitosan nanoparticles, pH 7 and 30 min of mixing time. Chitosan showed the highest performance under these conditions with removing percent 99.94% 80.85% 90.49% and 95.93% from Fe+2, Mn+2, Zn+2 and Cu+2 respectively

Comparison between physical properties of ring-spun yarn and compact yarns spun from different pneumatic compacting systems

A comparative study pertaining to physical and mechanical properties of ring-spun yarn vis-à-vis compact yarns spun using three different compacting systems has been reported. Rieter (K-44), Toyota (RX-240) and Suessen (Fiomax) spinning machines have been used and the condensing process of the fibres in the yarn cross-section as per these compact spinning systems is accomplished pneumatically. Thus, a yarn of linear density 5.9 tex (100 Ne) is spun on the spinning systems using Egyptian cotton of the type Giza 86. One way Anova together with least significant difference are employed to feature the means of the properties of spun yarns and a significant difference among them is observed. According to the performed statistical analysis, there is a significant difference between ring - spun yarn properties and each of the pnuematic compact spun yarns. These compact-spun yarns are also found to differ significantly in terms of their physical and mechanical properties; however, they are all found superior to the ring-spun yarn

Evaluation of Two Bone Anchored Appliances During En Masse Distalization of Maxillary Buccal Segment with Class II Patients; A Comparative Clinical Study

Objective: to assess quality of orthodontic tooth movement during distalization by two different skeletally anchored distalizing appliances. Patients and methods: the current study was applied on 22 orthodontic patients with class ΙΙ molar relationship. Patients were divided into two active groups; group Ι: include 11 patients treated by modified sagittal screw distalizer and group ΙΙ: include 11 patients treated by modified distal jet distalizer. Quality of distalization was assessed by the following measurements; first and second premolars root horizontal distance (mm), first and second molars root horizontal distance(mm), SNA, SNB, U1 to FH. Results: The highest change (%) in first molar root horizontal distance (mm) was recorded in group II with a decrease by -11.5 % in the left side and -11.4 % in the right side. Conclusion: Bone anchored Distal Jet and modified Sagittal screw distalizer provide an effective tool for treating mild to moderate class II malocclusion. But the modified distal jet produces high quality of distalization than the modified Sagittal screw distalizer

Effect of FSW Parameters on The Microstructure and Mechanical Properties of T-joints between Dissimilar Al-Alloys

The main purpose of this research is to develop T-joints between the aluminum AA 2024-T4 and AA 7075-T6 using friction stir welding.  The effect of tool geometries, tool traveling speed, and rotational rate in the welded T-joints were investigated and discussed. Three different tools were used with different shoulder to pin ratios 3.28, 3.36, and 4.31. After optimization, the best tool dimension has used with the different rotational and welding speeds. Three tool traverse speeds of 50, 75, and 100 mm/min were used. Two rotation rates of 800 rpm and 1000 rpm were applied. After FSW, at a number of the above FSW parameters' combinations, macrostructure and microstructure analyses were done using optical microscopy. In order to have an insight into the mechanical properties, hardness measurements and tensile testing were carried out. Using small shoulder to pin ratio produced visually unacceptable T-joint. Opposite happened by using the tool with 4.31 of shoulder to pin ratio. Furthermore, the results showed sound T-welds with no obvious defects at high rotational rate of 1000 rpm with the two used traveling speeds. Asymmetric temperature distribution was observed between the two sides, advance side (AS) and retreating side (RS

Characterization of Sidr (Ziziphus spp.) Honey from Different Geographical Origins

The current investigation was conducted to assess the melissopalynological, physicochemical, and biochemical properties, antimicrobial and antioxidant activities as well as total phenolic and total flavonoid contents of 794 Sidr honey samples collected from the Saudi market that had been imported from 12 different countries. Testing Sidr honey from different countries showed different levels of growth suppression observed against five drug resistant bacterial strains. The pathogenic strains were Staphylococcus aureus, Streptococcus mutans, Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa. The antimicrobial activity showed growth suppression levels which varied according to the origin of the honey. The comparative study of Sidr honeys revealed a strong correlation between total polyphenol and flavonoid contents and significant radical scavenging activities in particular Egyptian and Saudi Arabian honeys. The melissopalynological and physicochemical properties of different Sidr honeys complied with the recommendations of the WHO Codex Alimentarius, the European Union standards for honey quality, and the Gulf Technical Regulation on honey (GSO 147:2008-Standards Store-GCC Standardization Organization). It was concluded that Sidr honey from different geographical areas has the capacity to suppress the growth of pathogenic bacteria and perform significant radical scavenging activities

FORMULATION AND OPTIMIZATION OF ITRACONAZOLE PRONIOSOMES USING BOX BEHNKEN DESIGN

Objective: The aim of the present study was to obtain an optimized formula of itraconazole (ITC) proniosomes using Box Behnken design.Methods: Itraconazole proniosomes were prepared using span 60 and/or brij 35 as surfactants, cholesterol and lecithin as a penetration enhancer by slurry method. Various trials have been carried out for investigation of proniosomes. Parameters such as entrapment efficiency (EE%), in vitro drug release, zeta potential, vesicle size and Transmission Electron Microscope were assessed for evaluation of proniosomes.Results: Entrapment efficiency (EE%) was found to be between 78.56% and 95.46%. The release profile of itraconazole proniosomes occurred in two distinct phases, an initial phase for about 8 h, followed by a slow phase for 16 h. The release pattern shown by these formulations was Higuchi diffusion controlled mechanism. The zeta potential values for all itraconazole proniosomes were in the range of-21.71 to-34.53 mV which confirms their stability. All itraconazoleproniosomes formula was found to be nano-sized and were appeared to be spherical in shape with sharp boundaries. One way analysis of variance (ANOVA) study showed that HLB (X1) had the main effects on most responses (Y).Conclusion: Box behnken design facilitates optimization of the formulation ingredients on entrapment efficiency, in vitro release of itraconazole proniosomes, zeta potential and vesicle size. Finally, an optimum level of factors was provided by the optimization process

Short-term assessment of left ventricular function after coronary artery bypass grafting

Background: The effect of coronary artery bypass grafting on postoperative left ventricular function is still the subject of ongoing studies. The degree of recovery and its duration have not been precisely determined, and the published data are discordant. The objective of this study was to assess the effect of surgical revascularization on left ventricular systolic function. Methods: We prospectively studied 50 consecutive patients who underwent elective isolated coronary artery bypass grafting in the period from January 2017 to November 2017. All patients had echocardiography preoperatively, pre-discharge, and at 3 and 6 months postoperatively. Left ventricular end-systolic volume, left ventricular end-diastolic volume, stroke volume, and ejection fraction were measured in all patients. Results: The mean age was 57.22±7.04 years. The mean number of grafts was 2.60±1.02. Improvement in Canadian Cardiovascular Society (CCS) score from (2.72 ± 1.03) preoperatively to [(0.12 ± 0.39), p<0.001] after six months was achieved. Additionally, improvement in the patient New York Heart Association (NYHA) score occurred from (1.70 ± 0.97) preoperatively to [(0.12 ± 0.33), p<0.001] after six months. A significant improvement in left ventricular function occurred  as demonstrated by improvement in mean left ventricular ejection fraction from (54.14±9.80) % to  [(62.40 ± 4.18) %, p<0.001] at six months. The mean total hospital stay was 5.62±1.51 days. The mean total intensive care unit length of stay was 47.16±25.73 hours. Two patients (4%) had re-exploration for bleeding, and postoperative myocardial infarction occurred in three patients (6%).  One patient (2%) had postoperative neurocognitive dysfunction, and 3 patients (6%) had postoperative atrial fibrillation. Two patients (4%) suffered from superficial wound infection. There was no hospital mortality.   Conclusion: Patients undergoing CABG experienced an improvement in left ventricular contractile function at six months postoperatively. Further studies are required to evaluate the changes after 6 months