Effect of Dispersions of Al2O3 on the Physical and Mechanical Properties of Pure Copper and Copper-Nickel Alloy

This paper illustrates the mechanical and physical properties of pure Cu and Cu-Ni (50-50 wt. %) alloy mixed with Al2O3 (1-4 wt. %) as micro-particles reinforcement materials. The attained composite alloy specimens\u27 characteristics were estimated such as microstructure, relative density, electrical and thermal conductivity, hardness, and compression yield stress properties to adjust the suitable optimum percentage of reinforcing material which has the best physical and mechanical properties with different main matrix materials whether pure Cu powder or Cu-Ni mechanical alloy. The micron-sized Al2O3 was added to enhance the mechanical and physical properties of the pure Cu and Cu-Ni alloy composites. The electrical and thermal conductivity for pure Cu alloy composites were improved compared to the copper-nickel alloy matrix composites material. The hardness and compression yield stress of pure copper has enhancement values and for Cu-Ni alloy composites have enhancement values and for Cu-Ni base composites, hardness and compression yield stress have improved with the most positive enhancement values

Application of Short Fibers Reinforced Composites in Power Transmission Coupling

Abstract In this study the use of short glass, carbon and hybrid glass-carbon fibers reinforced polymeric composites in power transmission coupling is investigated. The presented work is generalized to thermoplastic and thermoset polymeric matrix composites. The effects of the constituents weight percentages, and average fibers length on the composite tensile strength and modulus are studied using the Taguchi design of experiments method. A new approach of Finite Element analysis is introduced to model the effect of the hybrid fibers random distribution and average fibers length among the volume of the matrix. Each fiber is simulated independently in the model as a three dimensional truss element embedded in the matrix. The FEA model is applied on the tensile specimen and then on the power transmission coupling simulation. Finally, the new approach of finite element analysis results on the coupling are validated

Application of Short Fibers Reinforced Composites in Power Transmission Coupling

<div><p>Abstract In this study the use of short glass, carbon and hybrid glass-carbon fibers reinforced polymeric composites in power transmission coupling is investigated. The presented work is generalized to thermoplastic and thermoset polymeric matrix composites. The effects of the constituents weight percentages, and average fibers length on the composite tensile strength and modulus are studied using the Taguchi design of experiments method. A new approach of Finite Element analysis is introduced to model the effect of the hybrid fibers random distribution and average fibers length among the volume of the matrix. Each fiber is simulated independently in the model as a three dimensional truss element embedded in the matrix. The FEA model is applied on the tensile specimen and then on the power transmission coupling simulation. Finally, the new approach of finite element analysis results on the coupling are validated.</p></div

Effect of holding time, thickness and heat treatment on microstructure and mechanical properties of compacted graphite cast iron

The effect of holding time, thickness and annealing heat treatment on the microstructure and some mechanical properties of compacted graphite iron (CGI) are studied. Samples of CGI are produced in Helwan factory for casting by using GGG 70 as base metal in a medium frequency induction furnace. The mechanical properties (tensile strength, and hardness) of the as-cast and after heat treatment samples are determined and the microstructure of the samples is examined using optical microscope. The results show that the mechanical properties and microstructure of CGI depend on holding time, thickness and annealing heat treatment; it is found that increasing the holding time from 10 min to 17 min results in lowering the Mg content from 0.031% to 0.021% and as a result lower nodularity was obtained. Lowering the thickness from 20 mm to 5 mm increases the tendency of dendritic structure as a result of increasing the cooling rate. The annealed samples with mainly ferritic matrix gave the lowest tensile strength and hardness value compared with the as-cast conditions. Keywords: Compacted graphite iron (CGI), Heat treatment, Microstructures, Mechanical propertie

Funktionelle Ergebnisse nach lasermikrochirurgischer Abtragung gutartiger Stimmlippenbefunde

Hintergrund: Insbesondere bei gutartigen Stimmlippenbefunden steht der Erhalt oder die Verbesserung der Stimmqualität im Focus des chirurgischen Vorgehens.Material und Methoden: Alle 173 Eingriffe fanden mit dem CO2-Laser unter phonochirurgischen Gesichtspunkten statt.Die Funktionsdiagnostik erfolgte präoperativ und 8 bis 12 Wochen postoperativ. Hierbei wurden die Stimmqualität und die Stimmleistung mit dem Göttinger Heiserkeitsdiagramm (GHD) sowie dem Dysphonia Severity Index (DSI) evaluiert und die Selbst-Einschätzung der Patienten mit dem Voice Handicap Index (VHI) bestimmt.Ergebnisse: Bei 106 Frauen und 67 Männern mit einem durchschnittichen Alter von 56 (±15) Jahren (min. 07 Jahre, max. 91 Jahre) wurden diverse gutartige Kehlkopfbefunde (Reinke-Oedeme, Polypen, Hyperkeratosen, Zysten, Laryngozelen, Papillome, Granulome, Stimmlippenknötchen, und seltene Befunde) operiert. Die histologische Befundsicherung erfolgte in allen Fällen.Unabhängig von den Ausgangsbefunden konnte die Stimmqualität in allen Fällen erhalten oder gebessert werden. Sowohl die Messwerte des GHD als auch des DSI und VHI stellen im Mittel die Befundbesserung dar.Diskussion: Die Ergebnisse zeigen, dass auch in der Phonochirurgie der CO2-Laser ein geeignetes Instrument ist. Die verwendeten Instrumente zur Evaluation der Stimmqualität und -leistung erlaubten die Quantifizierung der klinischen Befunde

Can Toxoplasma gondii Pave the Road for Dementia?

Dementia is an ominous neurological disease. Scientists proposed a link between its occurrence and the presence of Toxoplasma gondii (T. gondii). The long-term sequels of anti-Toxoplasma premunition, chiefly dominated by TNF-α, on the neurons and their receptors as the insulin-like growth factor-1 receptor (IGF-1R), which is tangled in cognition and synaptic plasticity, are still not clear. IGF-1R mediates its action via IGF-1, and its depletion is incorporated in the pathogenesis of dementia. The activated TNF-α signaling pathway induces NF-κβ that may induce or inhibit neurogenesis. This study speculates the potential impact of anti-Toxoplasma immune response on the expression of IGF-1R in chronic cerebral toxoplasmosis. The distributive pattern of T. gondii cysts was studied in association with TNF-α serum levels, the in situ expression of NF-κβ, and IGF-1R in mice using the low virulent ME-49 T. gondii strain. There was an elevation of the TNF-α serum level (p value ≤ 0.004) and significant upsurge in NF-κβ whereas IGF-1R was of low abundance (p value < 0.05) compared to the controls. TNF-α had a strong positive correlation with the intracerebral expression of NF-κβ (r value ≈ 0.943, p value ≈ 0.005) and a strong negative correlation to IGF-1R (r value -0.584 and -0.725 for area% and O.D., respectively). This activated TNF-α/NF-κβ keeps T. gondii under control at the expense of IGF-1R expression, depriving neurons of the effect of IGF-1, the receptor’s ligand. We therefore deduce that T. gondii immunopathological reaction may be a road paver for developing dementia

Effects of Lactobacilli acidophilus and/or spiramycin as an adjunct in toxoplasmosis infection challenged with diabetes

The current study assessed the anti-parasitic impact of probiotics on Toxoplasma gondii infection either solely or challenged with diabetes in Swiss albino mice. The study design encompassed group-A (diabetic), group-B (non-diabetic), and healthy controls (C). Each group was divided into infected-untreated (subgroup-1); infected and spiramycin-treated (subgroup-2); infected and probiotic-treated (subgroup-3); infected and spiramycin+ probiotic-treated (subgroup-4). Diabetic-untreated animals exhibited acute toxoplasmosis and higher cerebral parasite load. Overall, various treatments reduced intestinal pathology, improved body weight, and decreased mortalities; nevertheless, probiotic + spiramycin exhibited significant differences. On day 7 post-infection both PD-1 and IL-17A demonstrated higher scores in the intestine of diabetic-untreated mice compared with non-diabetics and healthy control; whereas, claudin-1 revealed worsening expression. Likewise, on day 104 post-infection cerebral PD-1 and IL-17A showed increased expressions in diabetic animals. Overall, treatment modalities revealed lower scores of PD-1 and IL-17A in non-diabetic subgroups compared with diabetics. Intestinal and cerebral expressions of IL-17A and PD-1 demonstrated positive correlations with cerebral parasite load. In conclusion, toxoplasmosis when challenged with diabetes showed massive pathological features and higher parasite load in the cerebral tissues. Probiotics are a promising adjunct to spiramycin by ameliorating IL-17A and PD-1 in the intestinal and cerebral tissues, improving the intestinal expression of claudin-1, and efficiently reducing the cerebral parasite load