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Deposition of Biocompatible Thin Films Using Glow Discharge

Thesis Info

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Author

Saleem, Sehrish

Program

PhD

Institute

Government College University Lahore

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2016

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/7579/1/Full%20Thesis.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725818837

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The present research is motivated to make an ideal biomaterial which possessed high strength, elastic modulus comparable to bone; good wear resistance and excellent biocompatibility. Since Ti and its alloys are light weight, possessed excellent mechanical strength, high corrosion resistance and good biocompatibility therefore they are frequently used in joint replacement, bone plates and screw, dental root implant, vascular stents and spinal fixation devices. Commercial pure (CP) titanium is a good candidate for biomedical application. However its low mechanical strength and surface hardness limits its use in load bearing applications. On other hand Ti6Al4V and NiTi alloys are two most useable Ti 23 alloys, but vanadium (V) and nickel (Ni) hampered their properties, as both are toxic and produce the allergic reaction. Therefore it is imperative to improve their surface properties to make them an ideal biomaterial. A plasma surface modification is an attractive method to improve the surface properties of biomaterials; because it is not only economic and efficient, but we can also tailor only surface properties without any change in bulk. In present research work we performed three experiments to improve the surface properties of Ti and its alloy using the glow discharge. In first experiment, titanium oxynitride films were deposited on NiTi samples by high vacuum magnetron sputtering for various nitrogen and oxygen gas flow rates. The composition of deposited film was characterized using X-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). The results reveal the presence of TiN, and rutile and anatase phases of TiO2 in the titanium oxynitride thin films. Energy dispersive spectroscopy (EDS) elemental mapping of samples after immersion in simulated body fluids (SBF) shows that Ni is depleted from the surface and cell cultures corroborate the enhanced biocompatibility in vitro. In second experiment, zirconium oxide nanostructure thin film has been deposited on the surface of Ti6Al4V alloy via plasma immersion ion implantation and deposition (PIII&D) technique at the various voltages 15, 20 and 25 KV. The chemical composition and surface morphology of deposited film is characterized by the X-ray photoelectron spectroscopy (XPS) and Atomic force microscope (AFM) respectively. The XPS results confirm the formation of ZrO2 film. AFM results show the formation of smooth film was formed with maximum roughness of 8.4 nm. The effects of the implantation voltages on the wear characteristics are also investigated by pin-on-disk test. It is observed that wear resistance improves with an increase in the applied voltage and is found to be maximum at 25 KV. Moreover the nanohardness is improved in treated specimens and is almost doubled as compared to untreated specimen at the maximum voltage. The variation in wear resistance and nanohardness is attributed to the formation of hard nanostructure ZrO2 film on substrate surface. In third experiment, Ti-Al-O composite film has been formed by using pulsed DC magnetron sputtering system at various powers (100, 150, 200 watt). The effect of deposited film on mechanical properties and biocompatibility of CP Ti has been studied. The composition of film has been examined through X-ray diffractometer (XRD). Surface morphology of deposited film was observed using atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques. It was found that surface roughness of film increase with increasing plasma excitation power. To determine the strength of film, tensile test was carried out using Universal testing machine. The hardness was also measured by Vickers 24 microhardness tester. The results show that composite film improved the mechanical properties such as YS, UTS and hardness of CP Ti without any reduction in percentage elongation. Moreover, the biocompatibility of deposited film also performs by culturing the MC3T3-E1 cell for three days. Results exhibit that composite film significantly improves the biocompatibility of titanium. Micrographs of cell culture indicate that better cells growth/proliferation (elongated morphology) is observed on film prepared at 150 watt.
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مولانا امین احسن اصلاحی

مولاناامین احسن اصلاحی
۱۶؍ دسمبر ۱۹۹۷؁ء کو جامعۃ الفلاح بلریا گنج میں یہ اندوہ ناک خبر سنی کہ مولانا امین احسن اصلاحی صاحب کی وفات ہوگئی، اناﷲ وانا الیہ راجعون۔
ادھر سال بھر سے اس کا کھٹکا لگا ہوا تھا کہ علم و کمال کا یہ مہر جہاں تاب غروب ہونے والا ہے۔ اور قرآن و حدیث کے بحر کا شناور اور غواص، علامہ حمید الدین فراہیؒ کا جانشین و ترجمان، ان کے علوم و معارف کا وارث و امین، حکمت قرآنی کا شارح و مبین، دین حق کا داعی و مبلغ، اسرار دین کا عارف و آشنا، شرک و توحید اور تقویٰ و نماز کا رمزو حقیقت شناس اپنے ہزاروں شاگردوں اور قدردانوں کو مغموم، اداس اور سوگوار چھوڑ کر جلد ہی سفر آخرت پر روانہ ہونے والا ہے۔
ابھی مولانا بدرالدین اصلاحی ناظم مدرستہ الاصلاح و دائرہ حمیدیہ کا غم تازہ ہی تھا کہ مدرسہ کا یہ گل سرسبد اور فکر حمید کا سب سے بڑا حامل و شیدائی بھی رخصت ہوگیا۔
کیا کہوں تاریکیٔ زندانِ غم اندھیر ہے
پنبہ نورِ صبح سے کم جس کے روزن میں نہیں
مولانا امین احسن اصلاحی صاحبؒ اعظم گڑھ شہر سے پورب میں واقع ایک گاؤن ’’بمہور‘‘ کے متوسط زمیندار گھرانے میں ۱۹۰۳؁ء میں پیدا ہوئے تھے۔ ان کے والد حافظ محمد مرتضےٰ صاحب ایک دیندار، متبعِ سنت اور تہجد گزار شخص تھے، وہ اپنے فرزند کو دینی تعلیم دلانا چاہتے تھے، اپنی اس تمنا کا ذکر انھوں نے اپنے ہم وطن دوست مولانا شبلی متکلم ندوی سے کیا جو علامہ شبلیؒ کے عزیز شاگرد اور مدرستہ الاصلاح سرائے میر کے منصبِ اہتمام پر فائز تھے۔ انھوں نے اسی مدرسہ میں مولانا امین احسن صاحب کا داخلہ کرادیا، جہاں انھوں نے ان سے اور دوسرے اساتذہ سے دینی علوم کی تحصیل کی، ان کو اپنی طالب علمی کے...

EFFECTS OF MILD, MODERATE AND INTENSE PHYSICAL ACTIVITY ON KNEE JOINT PROPRIOCEPTION IN HEALTHY YOUNG ADULTS

Aim: To evaluate the immediate effects of various activity levels on knee joint position sense. Methodology: Sixty males aged between 19 and 24 years, without any complains of discomfort or pain in the knee joint were selected from Bakhtawar Amin Hospital, Multan using convenience sampling, between April 2nd, 2019 to July 28th, 2019. Group A participants walked on the treadmill at a speed of 4 km/h for 5 min (n = 20). Group B participants ran on a treadmill at 6.4 km per hour for five minutes (n = 20). Group C participants sprinted on a treadmill at 8.5 km per hour for five minutes (n = 20). Results: Mean age of the subjects was 21.18±1.77. In the moderate physical activity group, the difference in the means in passive reproduction of the knee flexion angle of 20o observed was 1.40±2.39, (p-value 0.013), and similarly in intense physical activity was 1.75±3.58 (p-value 0.020). For the knee flexion angle of 40o, the difference in the means for moderate was 1.35±1.84 (p=0.002), and for the intense activity was 2.35±2.27 (p=0.012). However, in the group with mild physical activity, the difference in the means was statistically insignificant. Conclusion: The study indicated that physical activities of moderate level and intense level decrease the joint position sense appreciation at the knee joint in less active healthy individuals.

Identification of Temporal Specificity and Focus Time Estimation in News Documents

Time is deemed as paramount aspect in Information Retrieval (IR) and it pro foundly influence the interpretation as well as the users intention and expectation. The temporal patterns in a document or collection of documents plays a central role in the effectiveness of IR systems. The accurate discernment plays an immense role in persuading the time-based intention of a user. There exists a plethora of documents on the web wherein most on them contain the divergent temporal pat terns. Assimilation of these temporal patterns in IR is referred to as Temporal Information Retrieval (TIR). The comprehension of TIR systems is requisite to address the temporal intention of a user in an efficient manner. For time specific queries (i.e. query for an event), the relevant document must relate to the time period of the event. To attenuate the problem, the IR systems must: determine whether the document is temporal specific (i.e. focusing on single time period) and determine the focus time (to which the document content refers) of the documents. This thesis exploits the temporal features of the news documents to improve the retrieval effectiveness of IR systems.As best to our knowledge, this thesis is the pioneer study that focuses on the problem of temporal specificity in news docu ments. This thesis defines and evaluate novel approaches to determine the tem poral specificity in news documents. Thereafter, these approaches are utilized to classify news documents into three novel temporal classes. Furthermore, the study also considers 24 implicit temporal features of news documents to classify in to; a) High Temporal Specificity (HTS), b) Medium Temporal Specificity (MTS), and c) Low Temporal Specificity (LTS) classes. For such classification, Rule-based and Temporal Specificity Score (TSS) based classification approaches are proposed. In the former approach, news documents are classified using a proposed set of rules that are based on temporal features. The later approach classifies news documents based on a TSS score using the temporal features. The results of the proposed approaches are compared with four Machine Learning classification algorithms: Bayes Net, Support Vector Machine (SVM),Random Forest and Decision Tree. x The outcomes of the study indicate that the proposed rule-based classifier outper forms the four algorithms by achieving 82% accuracy, whereas TSS classification achieves 77% accuracy. In addition, to determine the focus time of news documents, the thesis contem plates the temporal nature of news documents. The type and structure of doc uments influence the performance of focus time detection methods. This thesis propose different splitting methods to split the news document into three logical sections by scrutinizing the inverted pyramid news paradigm. These methods in clude: the Paragraph based Method (PBM), the Words Based Method (WBM), the Sentence Based Method (SBM), and the Semantic Based Method (SeBM). Temporal expressions in each section are assigned weights using a linear regres sion model. Finally, a scoring function is used to calculate the temporal score for each time expression appearing in the document. Afterwards, these temporal expressions are ranked on the basis of their temporal score, where the most suit able expression appears on top. Two evaluation measures are used to evaluate the performance of proposed framework, a) precision score (P@1, P@2) and average error years. Precision score at position 1 (P@1) and position 2 (P@2) represent the correct estimation of focus at the top 2 positions in the ranked list of focus time whereas, average error year is the distance between the estimated year and the actual focus year of news document. The effectiveness of proposed method is evaluated on a diverse dataset of news related to popular events; the results re vealed that the proposed splitting methods achieved an average error of less than 5.6 years, whereas the SeBM achieved a high precision score of 0.35 and 0.77 at positions 1 and 2 respectively. The overall findings presented in this thesis demonstrate that the valuable tempo ral insights of documents can be used to enhance the performance of IR systems. The time aware information retrieval systems can adopt these findings to satisfy the user expectation for temporal queries.