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Study of Thermal Diffusive Properties of D-Block Transition Metals

Thesis Info

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Author

Zakir Ur Rehman

Program

PhD

Institute

Hazara University

City

Mansehra

Province

KPK

Country

Pakistan

Thesis Completing Year

2017

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/13120/1/Zakir_ur_Rehman_Physics_HSR_2016_HU_10.08.2018.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727400357

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The thermal diffusive properties of d-block transition metals are presented in this dissertation using semi-emperical methods. The microscopic study of the diffusion on the surfaces of the metals in presence of the adislands is carried out by molecular dynamics simulation (MD) technique. The diffusion mechanism of small 2- dimensional islands on the (111) surfaces of the transition metals, both for the homo- and hetero-diffusion of the adislands on the surfaces are studied, at different temperatures. The important atomic processes at the back of thermal diffusive behavior of the adislands as well as of the surfaces are elaborated. During the of small islets’ diffusion, the hoping events and zigzag concerted motion along with rotation are observed for Ag 1-atom to 3-atom islands while single-atom and multi-atom processes are discovered for Ag 4-atom and 5-atom islands, during the diffusion on Ag(111) surface. The diffusion coefficient, activation energy barrier and diffusion prefactor are determined for small Ag-islands diffusion on Ag(111) surface. A noticeable increase in the value of activation energy barrier is found with the increase in the number of atoms in Silver adislands on Silver (111) surface. A logical linear fit is observed for the diffusion coefficient for studied temperatures (300, 500, and 700 K). There is the same increasing and/or decreasing trends for both the diffusion coefficient and effective energy barrier are observed in both the self-learning Kinetic Monte Carlo (SLKMC) and MD calculations, for the temperature range of 300–700 K. The diffusion mechanism of small clusters of Copper (Cu) comprising of 1-9 atoms on Ag(111) surface is the major part of the study. Simulations carried out at three different temperatures of 300 K, 500 K and 700K, show dominant concerted motion for the Cu-smaller islands (containing 2 to 4 atoms), while shapechanging multiple-atom processes are found responsible for the diffusion of larger islands of Cu on Ag(111) surface. Arrhenius plots of the diffusion coefficients reveal the effective energy barrier less than 260 ± 5 meV for all Cu9/Ag(111). There is good scaling of the effective energy barrier with size, but most notably it remains constant for islands with 4 to 6 atoms of Cu on Ag(111) surface. The increase in the diffusion coefficient is within a factor of 10 at the said temperatures. The observed anharmonic features of the Cuadislands (breakage and pop-up) at Ag(111) surface as well as the surface anharmonicity of the Ag-substrate in the form of fissures, dislocations, vacancy creation and atomic exchange, are also the part of the dissertation. Regarding the observed diffusion mechanism of small clusters of Ag/Ag(111), the results are in a reasonable agreement with ab-initio density-functional theory calculations for Al/Al(111) while the energy barrier values are in the same range as the experimental values for Cu/Ag(111) and the theoretical values using ab-initio density-functional theory supplemented with embedded-atom method for Ag/Ag(111). For the smaller sized Copper islands on (111) surface of Silver, the variation in effective energy barrier with the island size is in good agreement with the experimental findings. These findings provide better input for KMC simulations and can supplement the experiments of the surface science.
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مل گئی یک مشت ان کو راحتِ دنیا و دیں


مل گئی یک مُشت اُن کو راحتِ دنیا و دیں
جن کی قسمت میں مدینے کی فضائیں ہو گئیں

نورِ ’’اقرا‘‘ کی ضیائیں ساتھ ساتھ آنے لگیں
جلوتوں میں آگئے جب غار کے خلوت نشیںؐ

صبحِ طیبہ میں بسی ایمان کی تابندگی
شامِ طیبہ میں نہاں ہے راحتِ قلبِ حزیں

بندگانِ ربِّ کعبہ کی یہی ہے بندگی
جس جگہ پہ نقشِ پائے مصطفی ہو خم جبیں

آسمانِ معرفت کی اُس کو رفعت مل گئی
مل گئی جس شخص کو طیبہ میں بس دو گز زمیں

بربطِ تخلیق کی آوازِ ہست و بود میں
خلقتِ نورِ محمدﷺ ہے صدائے اوّلیں

آپؐ کے دم سے جہانِ آب و گل میں تازگی
چہرئہ ارض و سما ہے آپؐ کے دم سے حسیں

خوبیٔ رفتار سے آگے مقامِ مصطفیؐ
وسعتِ پرواز کی حد سدرہ سے آگے کہیں

والہانہ اہلِ الفت کی نگاہوں نے کہا
چودھویں کے چاند سے ہے آپؐ کا چہرہ حسیں

مدحتِ ممدوحِ ربؐ کی وسعتوں کے سامنے
لفظ کے دامن میں تنگی کے سوا کچھ بھی نہیں

ہیں امامِ انبیاؐ ، اقصیٰ کی شب ، بدرالدجیٰ
مقتدی ہے ماہِ کنعاںؑ کی ادائے دل نشیں

شافعِ محشرؐ کے ابرو کا اشارا ہو گیا
مل گئی اُنؐ کی شفاعت سے ہمیں خلدِ بریں

کس طرح اُن کو ہو عرفانِؔ خدائے لم یزل
جن کو محبوبِ خداؐ کی ذات سے اُلفت نہیں

POLA SOSIALISASI PERGURUAN TINGGI DALAM MENINGKATKAN JUMLAH PENERIMAAN MAHASISWA BARU PADA IAIN PALU

This article discusses the effectiveness of the new student admission socialization program on the decision of the prospective student to enroll in the State Islamic Institute (IAIN) Palu. The problem studied is How are the efforts of socialization of new student admissions applied at IAIN Palu? What is the most effective socialization attempt for student candidate's admission at IAIN Palu? This research uses survey research design combined with descriptive qualitative analysis model. Data collection using questionnaire method supported by interview and collecting a documentations. The results showed that the socialization efforts applied in IAIN Palu was by utilizing mass media and school visit. An effective efforts of socialization for introducing institutions to the public is unprogrammed in schedules, they used word to word (door to door) and publicity promotion. Nevertheless, regular programmed socialization models are held regularly every day before the admission of new students, usually used advertising and “personal selling” through visits to schools, is still quite effective. While the main consideration factor for enrolling in IAIN Palu is the availability of courses appropriate to their interests.

Phytochemical, Ethnomedicinal and Bioassay Screening of Aerial Parts of Monotheca Buxifolia and Bosea Amherstiana

In this dissertation, Monotheca buxifolia and Bosea amherstiana were assessed for isolation and structural elucidation of their compounds. The phytochemical investigations of Monotheca buxifolia includes lauric acid (1), oleanolic acid (2) and bis (2-ethylhexyl) phthalate (3) while Bosea amherstiana incudes quercetin (4), gallic acid (5) and cinnamic acid (6). The pharmacological and biological activities of crude extract, different fractions thereof, and some compounds isolated in reasonable quantity from Monotheca buxifolia and Bosea amherstiana were investigated. The plants exhibited moisture, fat, fiber, nitrogen, and protein contents. Biological investigation shows significant antibacterial and phytotoxic activity exhibited by the secondary metabolites of Monotheca buxifolia and Bosea amherstiana against L. minor plants and cytotoxicity activity in brine shrimps. Moreover, Monotheca buxifolia and Bosea amherstiana showed moderate inhibition against urease and carbonic anhydrase. The potency of Monotheca buxifolia and Bosea amherstiana for inhibiting the growth of laryngeal cancer cells was determined by MTT assay at concentrations of 200 μg/ml and 150 μg/ml. The IC50 values of Monotheca buxifolia ranged from 80.6214 ± 1.89 μg/ml to 244.506 ± 2.43 μg/ml, while the IC50 values of Bosea amherstiana ranged from 108.564 ± 1.28 μg/ml to 206.053 ± 1.54 μg/ml. A comet assay was performed for the determination of DNA damage and the protective activity of the plant extracts against H2O2-induced human lymphocytes. The maximum protective effect of lymphocyte pretreatment was observed with the dichloromethane fraction of Monotheca buxifolia, which was 5.21 ± 0.030% tail DNA, while the Olive tail moment was 0.61 ± 0.03 compared with the rest of the treated Monotheca buxifolia samples. In Bosea amherstiana, the methanolic fraction had more protective effects against H2O2-induced lymphocytes, with 6.36 ± 2.23% tail DNA and an Olive tail moment of 0.84 ± 0.40. Antioxidant enzymes of lymphocytes were assessed. MB has an effective role in decreasing lipid peroxidase (TBAR) enzymes. The methanol, dichloromethane, and ethyl acetate fractions of MB were more effective (2.3, 2.4, and 2.7, respectively), while the aqueous fraction of MB increased the LPO slightly to 8.1. Both MB and MA had slight effects on the catalase (CAT) enzymes. The dichloromethane fraction of Bosea amherstiana increased the CAT enzymes slightly, while the aqueous fraction of Monotheca buxifolia lowered the concentration of CAT enzymes compared with the control. The dichloromethane fraction of MB slightly increased the peroxidase (POD) enzymes’ value to 31.2, while the aqueous extract of MB lowered the POD enzymes to 20.51. MB had no effect on decreasing or increasing superoxide dismutase (SOD), while BA contributed to lowering the SOD values. In terms of acute toxicity in vivo, both plants were found to be safe at all the test doses (500, 1,000, 1,500, and 2,000 mg/kg. Monotheca buxifolia and Bosea amherstiana (50, 100, and 150 mg/kg) dose dependently reduced abdominal constrictions in mice. Both plants exhibited significant (p < 0.0001) sedative effects at doses of 50, 150, and 150 mg/kg; however, they should be considered mild to moderate sedatives, as the sedation induced was for the less standard drug diazepam. Both plants markedly (p < 0.0001) reduced yeast-induced hyperthermia. CCl4 treatment considerably increased (p < 0.01) the activity of liver serum marker enzymes, such as liver LDH, serum LDH, ALP, AST, and ALT compared with the control group. The protective effect of Monotheca buxifolia was assessed by measuring the serum markers, assays of antioxidant enzymes, genotoxicity, and DNA damage. Monotheca buxifolia inverted the activities of the serum marker enzymes, and the cholesterol profile was damaged by CCl4 treatments. Activities of antioxidant enzymes of the liver tissue homogenates were assessed; CAT, SOD, and peroxidase (POD) were reduced with CCl4 administration, and they were retained with Monotheca buxifolia. The administration of Monotheca buxifolia and Bosea amherstiana reduced hepatic damage, with fewer or no fatty changes, expansion of blood vessels, or constant morphology of the hepatocytes in the control group. The isolated compounds of lauric acid, oleanolic acid, and bis(2-ethylhexyl) phthalate inhibited the growth of laryngeal cancer cells, as determined by MTT assay. The IC50 value for lauric acid was 56.4584 ± 1.20 μg/ml, that for oleanolic acid was 31.9421 ± 1.03 μg/ml, and that for bis(2-ethylhexyl) phthalate was 83.8019 ± 2.18 μg/ml. After 24 h of treatment, 29.5% of Hep G2 cells treated with lauric acid, 52.1% of those treated with oleanolic acid, and 22.4% of those treated with bis(2-ethylhexyl) phthalate were apoptotic.