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Effects of Geometrical Characteristics of Suture on fracture resistance of Walnut Shell

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Journal of Bionic Engineering 2023年第6期20卷 2732-2741页

作者： Peng Xu Lizhen Wang Jinglong Liu Yanxian Yue Yubo Fan Key Laboratory of Biomechanics and Mechanobiology(Beihang University) Ministry of EducationBeijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China School of Engineering Medicine Beihang UniversityBeijing100083China

Nut shells have good impact and fracture resistance,but many kinds of nut shells have suture structures with low bonding ***,the mechanism of impact and fracture resistance of nut shells as a whole is important to study,particularly given that sutures maintain low bonding *** this study,we investigated the effect of the geometrical characteristics of sutures(morphology,thickness,and number)on the overall fracture resistance of walnuts,based on mechanical tests of C-ring samples,microstructure analysis after cracking,quantitative analysis of suture geometric model,and numerical *** found that the cracking of walnuts was mainly caused by tensile stress,and the bonding strength was approximately 2.48±0.64 *** discovered that the thickness of the suture was 1.55±0.32 times thicker than the shell,which improved the fracture resistance ability by more than 28.4%.The undulating and inclined morphology of the walnut suture also increased the fracture ***,an appropriate suture number reduced the cracking of *** conclusion,our study sheds light on the physiological function of walnut sutures from a biomechanical perspective and provides useful references for designing fracture resistance measures in thin shell structures.

关键词： fracture resistance Walnut Suture Bonding strength Numerical simulations Biomechanics

EFFECT OF MECHANICAL PRE-CONDITIONING ON fracture resistance OF POLYPROPYLENE

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Chinese Journal of Polymer Science 2011年第3期29卷 318-324页

作者：王勇 Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong University

The effect of externally applied mechanical pre-conditioning, i.e. pre-impact treatment, on the fracture resistance was investigated for polypropylene （PP）. Impact strength was obtained via notched and/or unnotched samples. It has been shown that the pre-impact treatment is favorable to the improvement of the fracture resistance. The impact strength increases linearly with the applied pre-impact energy. Both optical and SEM results show that there are at least two possible mechanisms for the improvement of the fracture resistance. One is the crack blunting effect which is introduced to notched sample by pre-impact treatment, reducing the sensitivity of PP to the applied notch. The other is the formation of large amount of microvoids induced by pre-impact treatment, which changes the stress distribution and induces intensive plastic deformation of PP at the second impact measurement, leading to the improvement of the fracture resistance.

关键词： Mechanical pre-conditioning fracture resistance Microvoid PP.

fracture resistance and Failure Patterns of Open Apex Root Teeth with Different Posts after Endodontic Treatment

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Journal of Huazhong University of Science and Technology(Medical Sciences) 2011年第2期31卷 271-276页

作者：李秋慧闫萍陈智 Key Laboratory for Oral Biomedicine of Ministry of Education School and Hospital of Stomatology Wuhan University

The aim of this study is to investigate the influence of different posts on the fracture mechanics of endodontically-treated teeth with open apex. Forty-eight human maxillary anterior teeth were collected, and the root was transversely sectioned 12 mm under the cementoenamal junction （CEJ）. These samples were then randomly divided into two groups, i.e., minor diameter open apex root （group A） and major diameter open apex root （group B）, with mineral trioxide aggregate （MTA） placed into the apical 4 mm in the root canals. Subsequently, both groups were respectively further divided into three subgroups as follows： fiber-post （subgroup 1）, metal post （subgroup 2） and non-post （subgroup 3） group. Teeth were restored with a composite resin crown and tested by using a universal testing machine at the rate of 1 mm/min cross-head. Values of the maximum fracture resistance and failure patterns were recorded and compared among all subgroups. In addition, the changes of MTA properties were carefully examined via X-ray photography. Our results indicate that （1） In group A, the mean value of fracture resistance for teeth restored with fiber posts were statistically higher than that with either metal post or non-post; （2） In group B, there was no statistically significant difference in the mean value of fracture resistance among three subgroups; （3） No statistical significance in the mean value of fracture resistance was found between group A and group B; （4） The failure modes of most samples （58%） were irreparable; （5） MTA in two teeth developed cracks after loading tests. In conclusion, endodontically-treated teeth restored with fiber posts are more resistant to fracture than those restored with either metal posts or non-post, and most of the fracture modes are catastrophic in nature.

关键词： fiber post MTA open apex fracture resistance

fracture resistance of posterior teeth restored with modern restorative materials

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The Journal of Biomedical Research 2011年第6期25卷 418-424页

作者： Ibrahim M. Hamouda Salah H. Shehata Department of Biomaterials Mansoura University Al-Gomhoria St Mansoura 35516 Egypt Department of Conservative Dentistry Mansoura University Al-Gomhoria St Mansoura 35516 Egypt

We studied the fracture resistance of maxillary premolars restored with recent restorative materials. Fifty maxillary premolars were divided into five groups： Group 1 were unprepared teeth; Group 2 were teeth prepared without restoration; Group 3 were teeth restored with tetric ceram HB; Group 4 were teeth restored with InTen S; and Group 5 were teeth restored with Admira. The samples were tested using a universal testing machine. Peak loads at fracture were recorded. The teeth restored with Admira had the highest fracture resistance followed by those restored with InTen-S and tetric ceram HB. Prepared, unrestored teeth were the weakest group. There was a significant difference between the fracture resistance of intact teeth and the prepared, unrestored teeth. There was also a significant difference among the tested restorative materials. Teeth restored with Admira showed no significant difference when compared with the unprepared teeth. It was concluded that the teeth restored with Admira exhibited the highest fracture resistance.

关键词： fracture resistance composite resin adhesives mesio-occlusal-distal (MOD) cavities

Influence of masticatory fatigue on the fracture resistance of the pulpless teeth restored with quartz-fiber post-core and crown

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International Journal of Oral Science 2012年第4期4卷 218-220页

作者： Er-Min Nie Xia-Yun Chen Chun-Yuan Zhang Li-Li Qi Ying-He Huang Department of Prosthodontics The First Affiliated HospitalSun Yat-Sen University Department of Prosthodontics The Third Affiliated HospitalSun Yat- Sen University Department of Stomatology Taishan People's Hospital

To investigate whether masticatory fatigue affects the fracture resistance and pattern of lower premolars restored with quartz-fiber post-core and full crown, 44 single rooted lower premolars recently extracted from orthodontic patients were divided into two groups of 22 each. The crowns of all teeth were removed and endodontically treated and then restored with quartz-fiber post-core and full crown. Twenty-two teeth in one group were selected randomly and circularly loaded at 45° to the long axis of the teeth of 127.4 N at a 6 Hz frequency, and the other group was not delivered to cyclic loading and considered as control. Subsequently, all teeth in two groups were continually loaded to fail at 45° to the long axis of the teeth at a crosshead speed of 1 ***-1. The mean destructive force values were （733.88±254.99） and （869.14±280.26） N for the experimental and the control group, respectively, and no statistically significant differences were found between two groups （P〉O.05）. Bevel fracture and horizontal fracture in the neck of root were the major fracture mode of the specimens. Under the circumstances of this study, it seems that cyclic loading does not affect the fracture strength and pattern of the quartz-fiber post-core-crown complex.

关键词： fracture resistance masticatory fatigue pulpless teeth quartz-fiber

Influence of fiber posts on the fracture resistance of endodontically treated premolars with different dental defects

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International Journal of Oral Science 2013年第3期5卷 167-171页

作者： Qian-Qian Hou Yi-Ming Gao Lei Sun School of Medicine Shanghai Jiao Tong University Department of Stomatology Ruijin Hospital School of Medicine Shanghai Jiao Tong University

This study aimed to evaluate the influence of quartz fiber post placement on the fracture resistance of endodontically treated premolars with different dental defects under dynamic *** extracted single-rooted mandibular premolars were randomized into five *** group was prepared according to numbers of residual walls ranged from 0 to *** each group was divided into two subgroups with one restored with quartz fiber posts and the other without *** no-post groups,gutta percha point 2 mm below cemento-enamel junction was *** resin was adapted to the well and used to shape the core *** tooth was restored with a complete metal *** loading was carried out in a masticatory simulator with a nominal load of 50 N at 2 Hz for 300 000 loading *** a quasi-statically load was applied in a universal testing machine 306 to the long axis with a crosshead speed of 1 mm？min21until *** were analyzed with one-way analysis of variance and pairwise comparison（P,0.05）.No specimens failed during dynamic *** fracture resistance enhanced with the increase of numbers of coronal walls and the differences were significant（P,0.05）.Placement of fiber posts had a significant effect when fewer than two walls remained（P,0.05）,but it had no significant influence in groups with two,three or four walls（P.0.05）.Fiber post did not change failure mode,and the fracture pattern was mainly *** dentin walls need to be retained in *** no less than two walls remained,a fiber post is not always necessary.

关键词： dynamic loading fiber post fracture resistance residual wall

Amine functionalization on thermal and mechanical behaviors of graphite nanofibers-loaded epoxy composites

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Journal of Materials Science & Technology 2023年第20期151卷 80-88页

作者： Seong-Hwang Kim Sang-Jin Park Seul-Yi Lee Soo-Jin Park Department of Chemistry Inha University100 InharoIncheon 22212the Republic of Korea

With the growing demand for faster and more powerful computing,effective heat dissipation is essential to ensure the longevity,reliability,and high performance of electronic *** the field of modern electronic packaging materials,there is a great need for graphitic material-loaded polymeric composites(GPCs)with excellent thermal ***,the enhancement efficiency of GPCs is hindered by the agglomeration of fillers and the interfacial thermal resistance caused by the lack of continuous thermally conductive pathways between the filler and *** the interfaces between filler and matrix is of great importance in optimizing the performances of ***,we fabricated graphite nanofibers(GNF)-loaded nanocomposites using acid-functionalized GNF(AGNF)and acidtetraethylenepentamine-functionalized(TGNF)as a filler and epoxy resin as a matrix with different GNF loading contents to explore the interfacial properties of the *** optimal GNF loading for AGNF was 0.5 wt.%,while the TGNF showed 0.75 wt.%.The highest thermal conductivity(0.51 W m^(−1) K^(−1))and fracture toughness(25.8 MPa m^(1/2))values were found in the TGNF-loaded nanocomposites with a fraction of 0.75 wt.%,representing enhancements of∼145%and∼400%,respectively,compared to those of neat *** experimental data presented herein demonstrate that the interfacial properties play a significant role in enhancing the thermal and mechanical performances of the *** present approach is expected to serve as a valuable tool in the design of conductive polymeric nanocomposites for further practical applications,such as thermal interface materials and packaging of high-power electric devices.

关键词： Graphite nanofiber Nanocomposites Interfacial interaction Thermal conductivity fracture resistance

Analytical study of silane-based and wax-based additives on the interfacial bonding characteristics between natural rubber modified binder and different aggregate types

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Journal of Road Engineering 2023年第2期3卷 171-185页

作者： Ashiru Sani Mohd Rosli Mohd Hasan Khairul Anuar Shariff Najib Mukhtar Mohammad Nishat Akhtar Ikenna D.Uwanuakwa Qingli Dai Tracy Leh Xin Wong School of Civil Engineering Universiti Sains MalaysiaNibong Tebal 14300Malaysia Department of Civil Engineering Kano University of Science and TechnologyKano 3244Nigeria School of Materials and Mineral Resources Engineering Universiti Sains MalaysiaNibong Tebal 14300Malaysia Department of Civil Engineering Bayero UniversityKano 700241Nigeria School of Aerospace Engineering Universiti Sains MalaysiaNibong Tebal 14300Malaysia Department of Civil Engineering Near East UniversityMersin 99138Turkey Department of Civil EnvironmentalAnd Geospatial EngineeringMichigan Technological UniversityHoughtonMI 49931USA

The modification of asphalt binder with natural rubber latex(NR)significantly improves the rutting and fatigue resistance of asphalt ***,NR-modified binder is prone to low workability and wettability due to its high ***,this research focuses on examining the influences of silane and wax-based additives on the wettability of natural rubber-modified binders and the binder-aggregates adhesion *** this study,experimental and analytical approaches were *** contact angles of asphalt binder were measured using a goniometer through the sessile drop method with three solvents:deionised water,formamide,and *** Cþþalgorithm was adopted to compute the surface free energy(SFE)elements of the asphalt *** methods were employed to analyse the results based on the Young-Dupre equation,followed by linear regression to establish a correlation between the compatibility ratio(CR)and the SFE *** results inferred that modified asphalt binders with additives possessed improved moisture resistance,wherein dry work adhesion values were less than 210 mJ/m^(2)under granite interfaces,whereas the limestone interface exhibited higher dry adhesion values of 340 mJ/m^(2)and *** performance results were observed under wet adhesion conditions;with granite wet adhesive values observed below 120 mJ/m^(2),while limestone wet adhesion values were ascertained below 180 mJ/m^(2)for all tested samples and *** to the spread–ability coefficient results,the limestone interface has greater spread-ability than granite ***,compatibility ratio values indicated better compatibility of 1.9 or higher for tested samples under granite interfaces,whereas compatibility values of 1.7 and below were observed under limestone interfaces.

关键词： Bitumen Compatibility ratio fracture resistance Surface free energy Additiv

Impacts of conservative endodontic cavities on root canal therapy compare to traditional endodontic cavities in premolars

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Impacts of conservative endodontic cavities on root canal th...