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Home > Effect of Samarium Additions on Shape Memory and Thermomechanical Behavior of Iron Based Shape Memory Alloys

Effect of Samarium Additions on Shape Memory and Thermomechanical Behavior of Iron Based Shape Memory Alloys

Thesis Info

Access Option

External Link

Author

Shakoor, Rana Abdul

Program

PhD

Institute

Ghulam Ishaq Khan Institute of Engineering Sciences and Technology

City

Topi

Province

KPK

Country

Pakistan

Thesis Completing Year

2007

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/2075/1/29S.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725994398

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In the present work, a comparative study of the shape memory and thermomechanical behavior of four alloys containing different amount of samarium have been carried out at a strain rate of 0.08x10 -6 s -1 . After hot rolling, annealing and solution treatment, the alloy samples were tensile deformed at room temperature from 1% to 5% and were then recovered at 600̊C for 20 minutes repeatedly for six times to complete six training cycles. It has been found that the addition of samarium strengthens the austenitic matrix, increases the c/a ratio and reduces the grain size. It has been noticed that the addition of samarium (0.64 wt. %) improves the shape memory effect when the alloys were strained from 1% to 5%. This improvement in shape memory effect presumably can be regarded as the increase in strength, increase in c/a ratio and absence of ά (martensite). It has been further noticed that when samarium contents are gradually reduced from 0.64 % to 0.21% the shape memory effect decreases. The decrease in shape memory effect by the decrease in samarium contents can be attributed to decrease in strength, decrease in c/a ratio and formation of ά (martensite). It has been further noticed that the shape memory effect decreases with the increase in amount of strain. It is found that thermomechanical treatment (training) results in improvement of shape memory effect and has a significant influence on mechanical parameters like proof stress (σ 0.002 ), critical stress (σ 0.0008 ) and strain hardening exponent. The improvement in shape memory effect by thermomechanical treatment can be regarded as the effect of reduction in the values of proof stress and critical stress during training which facilitates the formation of ε (martensite). It has also been noticed that excessive training may result in the formation of ά (martensite) due to continuous softening of the alloy during training, thus degrading the shape memory effect. Finally, it has also been noticed that the addition of samarium increases the values of proof stress, critical stress and strain hardening exponent. Although the addition of samarium increases the values of proof stress, critical stress and strain hardening exponent yet it has not an adverse effect on shape memory effect.
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58. Al-Mujadilah/The Pleading Woman

58. Al-Mujadilah/The Pleading Woman

I/We begin by the Blessed Name of Allah

The Immensely Merciful to all, The Infinitely Compassionate to everyone.

58:01
a. Allah has heard the woman who was pleading with you, concerning the issue of her husband, and was complaining to Allah.
b. And Allah was hearing the conversation between you.
c. For Allah is All-Listening, All-Watching.

58:02
a. Those among you who estrange their women/wives by declaring them to be as their mothers;
b. should know that they can never be made as their mothers, for their mothers are only those who gave birth to them.
c. Indeed, they utter what is highly contemptuous, baseless and false.
d. Yet, assuredly, Allah will be Pardoning, Forgiving to the one who repudiates by zihaar through an atonement.

58:03
a. Those of the husbands who thus estrange their women/wives, then they wish to retract what they had uttered, let them free a captive before any skin-to-skin cohabitation between them.
b. Thus you are being warned so that you will never utter such contemptuous words again.
c. And Allah is Well-Aware of what you do.

58:04
a. And whoever cannot find any captive to set free or does not have the means of doing so, then let him keep Fast for two consecutive months, without any interruption, before any skin-to-skin cohabitation between them.
b. And whoever is unable for reasons of ill health or old age, then let him feed sixty poor people.
c. All this is decreed so that you may believe in Allah, HIS Injunctions and HIS Messenger.
d. And these are the limits set by Allah.
e. And the disbelievers/disobedient - those who will not comply...

MIND THE GAP DISCRIMINATION AND MANAGEMENT CHALLENGES AMONG FEMALE PHYSICAL THERAPISTS

Gender matters and has an impact, and it is intended to encourage readers to think about this important issue in clinical practice, education, research, and a wider context of public health1. Due to the dearth of gender theoretical knowledge that has been discovered within the field of physiotherapy, there are still many difficulties that women must overcome in today's world of gender equality and feminism for women's rights2. Historically, women are predominated in the physiotherapy profession, although this has gradually changed throughout the years3. According to Chartered Society of Physiotherapists (CSP) data for both practicing and non-practicing physiotherapists, the gender split changed from 76% female to 24% male to 74% female to 26% male between 2017 and 2020. Although women make up more than 50% of the physiotherapy workforce globally, they make up fewer than 50% of executive positions in national physiotherapy associations3.

Studies on Histology and Microbiology of Teat and Streak Canal and Therapeutic Efficacy of Partial Vs Full Insertion of Antibiotic Syringe Cannula in Buffaloes and Cows

The present study was undertaken to determine the comparative prevalence of streak canal infections in buffalo and cow and to determine the comparative dimensional features of streak canal these two dairy species. In addition, comparative efficacy of partial or full insertion of teat cannula of a dry period antibiotic formulation in buffalo and cow was determined. Duplicate streak canal swab and quarter foremilk samples taken from 20 lactating buffaloes and 20 lactating cows were cultured and isolates identified. Length and width of streak canal of buffalo and cow (n = 20 each) was determined by Vernier caliper after incising the teats collected from abattoir. An in vivo comparative radiographic analysis of streak canal of buffaloes and cows (n = 20 each) was performed after infusion of 0.25ml of 5% barium sulphate into each teat followed by radiographic imaging and measurement of streak canal length and width from the image. In another phase of the study, efficacy of partial insertion vs. full insertion of teat cannula of a commercial cephapirin benzathine dry period antibiotic formulation (Cefa-Dri®) in the prevention of new intramammary infections and treatment of existing infections was evaluated on 20 buffaloes and 20 cows. Results: Seventy three (91.25%) and 59 (73.75%) of streak canal swab samples of cow and buffalo respectively were found infected. Staphylococcus aureus was the most frequent isolate both in cow and buffalo accounting respectively for 34 and 18 of total isolates (n = 106 for cow; n = 78 for buffalo) recovered from streak canal. Forty four (55%) and 18 (22.5%) of quarter foremilk samples of cow and buffalo respectively were infected. Staphylococcus aureus was the frequent isolate recovered from milk samples of both cows and buffaloes accounting respectively for 25.49% and 18.18% of total milk isolates. The mean values of streak canal length determined by Vernier caliper in cow and buffalo respectively were 9.78 ± 1.20 and 9.96 ± 1.44 mm whereas the mean width was 0.9 ± 0.12 and 0.98 ± 0.23 mm; both dimensions being non significantly different in the two dairy species. The mean length (9.34 ± 1.01mm) of streak canal of cow determined from radiographic image differed non- significantly (p = 0.105) from the mean length (9.97±1.36mm) of streak canal of buffalo. Similarly, mean width of streak canal of cow (0.9±0.09mm) differed non-significantly (p = 0.192) from the mean width of streak canal of buffalo (0.94±0.10mm). Thickness of epithelium of streak canal of buffalo (357.19 ± 4.8μ) was highly significantly (p = 0.001) more than thickness of epithelium of streak canal of cows (327.25±5.91μ). Similarly, thickness of keratin layer of streak canal of buffalo (154.7±6.34μ) was highly significantly (p = 0.001) greater than the thickness of keratin layer of streak canal of cow (101.3±4.11μ). As also was the case for muscle sphincter thickness around streak canal. Fürstenberg’s rosette folds were highly significantly (p = 0.001) thicker in buffalo (13.4±0.12) than in cow (12.75±0.2). Mitotic index of streak canal of cow and buffalo also differed significantly (p = 0.038); being greater in cow than in buffalo. Seventeen new intramammary quarters infections were detected in 40 quarters of cows treated by full insertion of dry intramammary treatment syringe (Cefa-Dri®, Forte Dodge, USA) cannula. The corresponding figure for 40 cow quarters treated by partial insertion of the same antibiotic dry period formulation was 6. Nine new intramammary infections developed over dry period in 40 quarters of buffaloes treated by full insertion of treatment syringe (Cefa-Dri®, Forte Dodge, USA) cannula. The corresponding figure for 40 buffalo quarters treated by partial insertion of the same antibiotic dry period formulation was 3. A total of 20 quarters of 10 cows were found infected by various mastitis pathogens at drying off in full insertion treatment group. Thirteen of these quarters were found cured after calving as no organism could be isolated from samples collected at calving and those collected biweekly for 3 months after calving. In the partial treatment group, of the 22 quarters, 18 were cured. Thus the cure rate (81.8%) in the partial insertion treatment group was significantly higher than in the full insertion treatment group in cows. Ten of the 14 (71.4%) infected quarters of buffaloes were cured when Cefa-Dri® intramammary tube was used by full insertion method. The corresponding cure rate by partial insertion of the same intramammary preparation was 84.6% (11 of 13 infected quarters being microbiological negative at calving as well as 3 months following calving of buffaloes). All in all, the results of comparative histomorphological examination of streak canal of cow and buffalo as well as the results of comparative efficacy trial of partial vs. full insertion of cannula of dry period antibiotic treatment syringe suggest that both the dairy species should be treated at drying off by using partial insertion of dry period intramammary antibiotic formulation.