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Microstructure and mechanical properties of cast and heat treated Ti-6.55Al-3.41Mo-1.77Zr alloy

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Transactions of nonferrous Metals Society of China 2013年第12期23卷 3517-3524页

作者： Khaled M.IBRAHIM Abdel Moty M.EL-HAKEEM ramadan n.elshaer Certral Metallurgical R&D Institute Benha University

α＋βtitanium alloy with a composition of Ti-6.55Al-3.41Mo-1.77Zr （mass fraction,%） was cast into bars in a graphite mould using vacuum induction skull melting furnace （ISM）. The cast bars were hot swaged at 700 °C and then heat treated by two different regimes which resulted in fine and coarse lamella structures, respectively. The grain size of the as-cast structure was estimated to be 660 μm and the swaged samples obtained a very fine grain size in the range of 50 μm. The overall best combination of hardness, tensile properties, and wear resistance of theα＋βtitanium alloy was achieved by heat treating the samples at 1050 °C for getting fine lamellar structure. The maximum compression strength was reported for the heat treated samples at 800 °C with coarse lamella structure. The minimum wear rate was reported for the heat treated samples with fine lamellar structure and the maximum wear rate was obtained for as-cast samples due to its coarse and heterogeneity microstructure.

关键词： α+βTi-alloy casting solution treatment microstructure mechanical properties

Diagnostic accuracy of ePOS score in predicting DnR labeling after ICU admission:A prospective observational study(ePOS-DnR)

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Journal of Intensive Medicine 2024年第2期4卷 216-221页

作者： Omar E.ramadan Ahmed F.Mady Mohammed A.Al-Odat Ahmed n.Balshi Ahmed W.Aletreby Taisy J.Stephen Sheena R.Diolaso Jennifer Q.Gano Waleed Th.Aletreby Department of Critical Care King Saud Medical CityRiyadhSaudi Arabia Anesthesia Department Faculty of MedicineAin Shams UniversityCairoEgypt Anesthesia Department Faculty of MedicineTanta UniversityTantaEgypt Faculty of Medicine Alexandria UniversityAlexandriaEgypt nursing Department King Saud Medical CityRiyadhSaudi Arabia

Background Resuscitation can sometimes be futile and making a do-not-resuscitate(DnR)decision is in the best interest of the *** electronic poor outcome screening(ePOS)score was developed to predict 6-month poor outcomes of critically ill *** explored the diagnostic accuracy of the ePOS score in predicting DnR decisions in the intensive care unit(ICU).Methods This study was conducted at the ICU of a tertiary referral hospital in Saudi Arabia between March and May ***,we calculated ePOS scores for all eligible consecutive admissions after 48 h in the ICU and recorded the DnR *** ability of the score to predict DnR was explored using logistic ***'s ideal cut-off value was calculated using the DeLong method,and different diagnostic accuracy measures were generated with corresponding 95%confidence intervals(CIs).Results We enrolled 857 patients,125 received a DnR order and 732 did *** average ePOS score of DnR and non-DnR patients was 28.2±10.7 and 15.2±9.7,*** score,as a predictor of DnR order,had an area under receiver operator characteristic(AUROC)curve of 81.8%(95%CI:79.0 to 84.3,Pn's ideal cut-off value>17 was associated with a sensitivity of 87.2(95%CI:80.0 to 92.5,Pnegative predictive value of 96.7(95%CI:95.1 to 98.3,Pnd diagnostic odds ratio 12.1(95%CI:7.0 to 20.8,Pnclusions In this study,the ePOS score performed well as a diagnostic test for patients who will be labeled as DnR during their ICU stay.A cut-off score>17 may help guide clinical decisions to withhold or commence resuscitative measures.

关键词： Do-not-resuscitate(DnR) Resuscitation Intensive care unit(ICU) Diagnostic accuracy Sensitivity Specificity

Hyoscine n-butylbromide inhalation:they know,how about you?

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World Journal of Emergency Medicine 2023年第1期14卷 81-82页

作者： Hayri ramadan Department of Emergency Medicine Ankara Training and Research HospitalUniversity of Health SciencesAnkara 06230Turkey

Dear editor,Hyoscine n-butylbromide(HnB)is a quaternary ammonium compound with an anticholinergic effect and is commonly used as an antispasmodic drug.[1,2]HnB decreases motility in the gastrointestinal and genitourin... 详细信息

关键词： editor quaternary ammonium

Fatigue Performance of Heat Treated TC21 Ti-Alloy

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Open Journal of Metal 2019年第2期9卷 11-18页

作者： ramadan n. elshaer Khaled M. Ibrahim Azza F. Barakat Reham R. Abbas Tabbin Institute for Metallurgical Studies Cairo Egypt Central Metallurgical R & D Institute Cairo Egypt Faculty of Engineering Helwan University Cairo Egypt Faculty of Engineering Suez University Suez Egypt

TC21 is considered a new titanium alloy that is used in aircraft applications as a replacement for the famous Ti-6Al-4V alloy due to its high strength. The effect of single and duplex stage heat treatments on fatigue behavior of TC21 Ti-alloy (Ti-6Al-2Sn-2Zr-3Mo-1Cr-2nb-0.09Si, wt.%) was investigated. Two heat treatment cycles were applied on as-received TC21 Ti-alloy. The first cycle was called single stage heat treatment (SSHT). The other cycle was named duplex stage heat treatment (DSHT). Typical microstructures of SSHT & DSHT composed of primary equiaxed α phase, residual β phase and secondary α phase (αs). Secondary α phase was precipitated in the residual β phase due to low cooling rate using air cooling and aging treatment. Morphology of α phase does not change after solution treatments, while their volume fraction and grain size were changed. SSHT showed the highest fatigue strength of 868 MPa due to high tensile strength, hardness and existing of high percentages of residual β phase in the microstructure. However, DSHT reported lower fatigue strength of 743 MPa due to increasing grain size of α phase. The fracture surface of fatigue samples showed cleavage ductile fracture mode for both heat treatment cycles.

关键词： TC21 Ti-Alloy Solution Treatment Microstructure Hardness Tensile Fatigue

Effect of Heat Treatment Processes on Microstructure and Mechanical Behavior of TC21 Titanium Alloy

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Open Journal of Metal 2017年第3期7卷 39-57页

作者： ramadan n. elshaer Khaled M. Ibrahim Azza F. Barakat Reham R. Abbas Central Metallurgical R & D Institute Cairo Egypt College of Engineering Taibah University Medina KSA Faculty of Engineering Helwan University Cairo Egypt

The effect of heat treatment on microstructure and tensile properties as well as wear behavior on TC21 (Ti-6Al-2Sn-2Zr-3Mo-1Cr-2nb-Si, wt.%) Ti-alloy was investigated. The samples were solution treated at 900°C for 15 min followed by furnace cooling to 800°C with a cooling rate 1°C/min and holding for 20 min, then the samples cooled down to room temperature either using water quenching (WQ) or air cooling (AC). Consequently, aging treatment was applied at 575°C for 4 hr. The microstructure feature showed a secondary α phase (αs) precipitated in residual β phase due to the step cooling from 900°C to 800°C inside furnace as well as the aging treatment. The highest wear rate was obtained for WQ samples due to increasing in volume fraction of αp (58%). However, the lowest wear rate was reported for WQ + Aging samples due to the high hardness. Optimum mechanical properties of the studied TC21 Ti-alloy were obtained for AC + Aging condition. A better combination of hardness, tensile properties, and wear resistance was achieved for AC + Aging samples, although their wear resistance was found to be slightly lower than that of WQ + Aging samples.

关键词： TC21 Ti-Alloy Cooling Rate Aging Microstructure Tensile Properties Wear

Influence of Plastic Deformation and Aging Process on Microstructure and Tensile Properties of Cast Ti-6Al-2Sn-2Zr-2Mo-1.5Cr-2nb-0.1Si Alloy

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Open Journal of Metal 2021年第2期11卷 11-20页

作者： Mostafa S. S. El-Deeb Khaled M. Ibrahim S. S. Mohamed ramadan n. elshaer Modern Academy for Engineering and Technology Cairo Egypt Central Metallurgical R & D Institute Cairo Egypt Shoubra Faculty of Engineering Benha University Cairo Egypt Tabbin Institute for Metallurgical Studies Cairo Egypt

In the present work, titanium alloy with a composition of Ti-6.5Al-3Mo-1.9nb-2.2Sn-2.2Zr-1.5Cr (TC21) was subjected to plastic deformation and aging processes. A Plastic deformation at room temperature with 2%, 3% and 4% stroke strain was applied on the studied samples. Then, the samples aged at 575°C for 4 hr. By applying different plastic deformation ratios, the structure revealed an elongated and thin β-phase embedded in an α-phase. Secondary α-platelets were precipitated in the residual β-phase. Maximum hardness (HV440) was obtained for 4% deformed + aged samples. Minimum hardness (HV320) was recorded for the as-cast samples without deformation. The highest ultimate tensile strength of 1311 MPa was obtained for 4% deformed + aged samples due to presence of high amount of dislocation density as well as precipitation of secondary α-platelets in the residual β-phase. The lowest ultimate tensile strength of 1020 MPa was reported for as-cast samples. Maximum elongation of 14% was registered for 4% deformed + aged samples and minimum one of 3% was obtained for as-cast samples. Hence, strain hardening + aging can enhance considerably the elongation of TC21 Ti-alloy up to 366% and 133% in case of applying 4% deformation + aged compared to as-cast and aged samples without applying plastic deformation, respectively.

关键词： TC21 Ti-Alloy Strain Hardening Microstructure Aging Hardness Tensile

Determination of Phase Transformation for TC21 Ti-Alloy by Dilatometry Method

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Open Journal of Metal 2019年第1期9卷 1-10页

作者： ramadan n. elshaer Khaled M. Ibrahim Azza F. Barakat Ahmed I. Farahat Reham R. Abbas Tabbin Institute for Metallurgical Studies Cairo Egypt Central Metallurgical R & D Institute Cairo Egypt Faculty of Engineering Helwan University Cairo Egypt Faculty of Engineering Suez University Suez Egypt

The α + β ? β phase transformation kinetics of TC21 Ti-alloy during continuous heating and cooling were studied using a dilatometric technique. Dilatometric heating curve exhibited that two characteristic reflection points can be observed with increasing the heating temperature. Ts referred to the initial transformation temperature of α + β → β and Tf referred to the final transformation temperature of α + β → β. Ts was reported at 720°C, whereas the corresponding Tf was obtained at 950°C. The initial and final transforming temperatures by the first derivative curve were reported at 730°C and 955°C, respectively, which are close to the values obtained in the dilatometric heating curve. Dilatometric cooling curve showed that the starting temperature of β → β + α phase transformation was 880°C;however, the corresponding finishing temperature was 670°C. The starting and finishing temperatures using the first derivative curve were obtained at 665°C and 885°C, respectively. The first derivative for the studied dilatometric heating and cooling curves showed that the starting and finishing temperatures of α + β ? β phase transformation were more accurate and objective. Results show the α + β → β transformation heating curve exhibits a typical S-shaped pattern.

关键词： TC21 Ti-Alloy Phase Transformation Dilatometry Heating Cooling

Could ketamine be the answer to treating treatment-resistant major depressive disorder?

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General Psychiatry 2020年第5期33卷 296-300页

作者： Abdullah Mohammed ramadan Islam Ahmed Mansour Psychiatry Mansoura University Faculty of MedicineMansouraEgypt

Major depressive disorder(MDD)is a common,serious,debilitating condition affecting 350 million people worldwide,which remains to be unsatisfactorily treated with 53%of patients still complaining of symptoms after completing their courses with the correct ***,which was approved by the Food and Drug Administration in 2019,is a potential treatment option for those recalcitrant *** mechanism of ketamine is not fully understood,but as type it is classified as an n-methyl-D-aspartate(nMDA)glutamate receptor antagonist,and can be given intravenously,intranasally and *** is used to treat treatment-resistant depression,depression associated with suicidal ideation,mood and anxiety disorders and depressions associated with either type of bipolar *** ketamine is considered relatively safe,several side effects have been reported with the major ones being psychiatric in the form of worsening mood,anxiety and agitation;psychotomimetic in the form of dissociation,perceptual disturbance and abnormal sensations;cardiovascular in the form of increased blood pressure and increased heart rate;and neurological in the form of headache and *** is still not approved worldwide for usage in patients with treatment-resistant MDD,but if it is approved sometime in the future with relatively fewer side effects,it is expected to significantly save millions of dollars spent yearly on patients with treatment-resistant depression and that will lift this major burden off the shoulders of healthcare *** study was designed to measure the effects of ketamine,an nMDA receptor antagonist,on patients with treatment-resistant MDD and to analyse the concept that makes it different and relatively safer than other major antidepressants like selective serotonin reuptake inhibitors,monoamine oxidase inhibitors and TCAs(tricyclic antidepressants).

关键词： ketamine dosage sensation

Structural and Tectonic Evolution of El-Faiyum Depression,north Western Desert,Egypt Based on Analysis of Landsat ETM+,and SRTM Data

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Journal of Earth Science 2011年第1期22卷 75-100页

作者： Timothy M Kusky Talaat M ramadan Mahmoud M Hassaan Safwat Gabr Three Gorges Research Center for Geo-hazard State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences The Geological Applications and Mineral Resources Division National Authority for Remote Sensing and Space Sciences (NARSS) Cairo Egypt

False color Landsat ETM＋（bands 7, 4, 2 in RGB） and SRTM images of the EI-Faiyum depression, Egypt, highlights major nE-SW faults and other lineaments trending nW-SE and n-S. Airborne magnetic data reveal some E-W subsurface faults which are not recognized on Landsat ETM＋ and SRTM images. Ratio images （5/7, 3/1, 4/3） and （5/7, 5/1, 4） were used for lithological discrimination of different rock types. The EI-Faiyum area is occupied by sedimentary rocks of Middle Eocene, Upper Eocene, Oligocene, Lower Miocene, Pliocene, Pleistocene and Holocene. Understanding the structural regime of EI-Faiyum depression in the Western Desert of Egypt is significant in relation to the neotectonics of the nile Delta and to the development of new communities west of the delta. The area is covered by Late Cretaceous, Middle to Late Eocene deposits, Oligocene deposits （comprising fluviatile sediments and basalt sheets） and Pliocene and Quaternary alluvium and sand deposits. new geological and structural maps were prepared at a scale of 1 ： 100 000 using Landsat ETM＋ and SRTM images coupled with extensive field work. The major structural trends are E-W, EnE, nS and nW--the same trends observed elsewhere in north Africa from nW Sudan to nE Egypt including north and central Sinai. EI-Faiyum depression is a structurally-controlled tectonic basin, marked by northeast-striking faults along its northern margin. These faults are parallel to similar faults of the Syrian arc fold belt, which includes a group of related faults, folds, push-up structures, and basins. Qarun Lake is located in the northern part of EI-Faiyum depression, at a right-step between two strands of the nE striking fault system. We have suggested elsewhere that EI-Faiyum depression is a pull-apart basin related to extension between these mismatched strands of strike-slip faults. The E-W structures are probably related to the relative motion between south Europe and north Egypt and closure of the neotethys. The continuation of t

关键词： Egypt EI-Faiyum Syrian arc fold belt pull-apart basin Western Desert of Egypt.