scholarly journals Type I Fracture Toughness Test of Rock-like Materials Based on the Particle Flow Method

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Ling Yue ◽  
Bangyong Yu ◽  
Chengxi Zhao ◽  
Fei Guo ◽  
Fei Huang
Keyword(s):  
Fracture Toughness ◽  
Loading Rate ◽  
Numerical Test ◽  
Particle Flow ◽  
Type I ◽  
Fracture Toughness Test ◽  
Test Results ◽  
Flow Method ◽  
Group A ◽  
Group B

In order to investigate the feasibility and reliability of the three-dimensional particle flow method in simulating the type I fracture toughness test, four types of numerical samples were established by particle flow code PFC3D: straight crack three-point bending (SC3PB), edge cracked flattened semicircular disc (ECFSD), cracked chevron notched Brazilian disc (CCNBD), and edge cracked flattened ring (ECFR). Three models with different strength parameters (group A, group B, and group C) were established for each type, in which group A parameters are obtained from the concrete model, group B parameters are applied for simulating marble, and group C parameters are for granite. The type I fracture toughness and the failure form of each model are obtained by conducting the numerical test, and the curves of load versus displacement of loading point are recorded. The numerical test results show that, with the same strength parameter, the maximum difference in test results of each specimen type is 0.39 MPa·m1/2. The KIC of ECFR specimen is 0.13–0.28 MPa·m1/2 smaller than that of CCNBD specimen, and the KIC of ECFSD specimen is slightly higher than that of CCNBD sample. The KIC of SC3PB specimen is 0.06–0.21 MPa·m1/2 smaller than that of the CCNBD sample. When the loading rate is less than 0.01 m/s, the effect of loading rate on fracture toughness can be reduced to less than 0.1 MPa·m1/2.

scholarly journals Effect of Delayed Light-Curing Through a Zirconia Disc on Microhardness and Fracture Toughness of Two Types of Dual-Cure Cement

2019 ◽  
Author(s):  
Pouran Samimi ◽  
Sara Kaveh ◽  
Maryam Khoroushi
Keyword(s):  
Fracture Toughness ◽  
Delay Group ◽  
Fracture Toughness Test ◽  
Irradiation Group ◽  
Significant Difference ◽  
Group A ◽  
Light Curing ◽  
Group B ◽  
Post Hoc ◽  
Group D

Objectives: Photopolymerization immediately sets dual-cure cements and prevents the continuation of chemical polymerization. Delayed light-curing allows the chemical process to continue up to the point before starting irradiation; however, there is a controversy in this respect. The present study evaluates the effect of delayed light-curing through a zirconia disc on the microhardness and fracture toughness (KIC) of two types of dual-cure cement. Materials and Methods: Samples measuring 25×5×3 mm3 were prepared for fracture toughness test, and discs measuring 5 mm in diameter and 3 mm in thickness were prepared for microhardness test using Bifix and BisCem cements. Light-curing protocols were as follows: immediate light-curing (group A), a 2-minute delay (group B), a 5-minute delay (group C), direct irradiation (group D), and no irradiation (group E). In groups A to C, light-curing was carried out through a zirconia disc. Data were analyzed by two-way and one-way analysis of variance (ANOVA), post-hoc Tukey's test, and Kruskal-Wallis test at 95% confidence interval. Results: There was a significant difference in the microhardness of the cements (P=0.00). Delayed light-curing had no effect on microhardness (P=0.080). The microhardness of BisCem in group E was significantly lower than that in group D (P=0.015). The fracture toughness of Bifix in groups B and C was significantly different than that in group E and BisCem groups. Conclusions: Under the limitations of our study, delayed light-curing had different effects on microhardness and fracture toughness. Differences in light-curing protocols resulted in different effects based on the cement type. Light-curing is recommended to achieve optimal mechanical properties.

scholarly journals The Effect of Loading Rate on Fracture Toughness of Concrete using Type I Fracture Toughness Test Flattened Brazilian Disc (FBD) Mode

2021 ◽  
Vol 921 (1) ◽  
pp. 012072
Author(s):  
A Yaqin ◽  
Djamaluddin ◽  
N F Qaidahiyani
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Loading Rate ◽  
Physical And Mechanical Properties ◽  
Open Pit ◽  
Type I ◽  
Fracture Toughness Test ◽  
Brazilian Disc ◽  
Toughness Test ◽  
Rock Anisotropy

Abstract Mining activities in open pit and underground mines will always be associated with rock breaking or stripping activities (both mechanical and blasting), so that this can affect the structure and strength of rocks. The strength of the rock is strongly influenced by the presence of initial cracks (pre-existing cracks) and rock anisotropy conditions associated with discontinuous plane conditions. Fracture mechanics is a science that illustrates how a fracture can occur and propagate during applied stress on material. The main parameter in fracture mechanics is called fracture toughness which shows the resistance of the material to propagate the crack. There are several mode in determining type I fracture toughness, one of which is type I fracture toughness Flattened Brazilian Disc (FBD) mode. Type I fracture toughness test is carried out using a compression machine in a laboratory and is conducted on concrete samples consisting of 3 (three) various samples, with a ratio of cement and sand composition of 1:1, 1:2, and 2:1. This test also uses different loading rate values, namely 2.50 mm/min, 2.70 mm/min, and 2.83 mm/min. The results of the type I fracture toughness value from each loading rate will be compared to determine the effect of the loading rate on the value of type I fracture toughness. The obtained fracture toughness value is also related to the physical and mechanical properties of the samples. Based on the results of tests, it can be seen that the loading rate affects the value of fracture toughness, the increase in fracture toughness value is followed by the higher loading rate. In addition, it can be seen that the fracture toughness value is directly proportional to the uniaxial compressive strength value and the indirect tensile strength value. The average correlation value obtained is R2 = 0.9884 (indicating a strong relationship).

scholarly journals The Structuring and Empowerment Policy of Losari Beach Street Vendors Based on The Concept of Smart City

2021 ◽  
Vol 921 (1) ◽  
pp. 012059
Author(s):  
P S Ahdi ◽  
A Akil ◽  
M Ramli
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Loading Rate ◽  
Physical And Mechanical Properties ◽  
Strong Relationship ◽  
Rock Breaking ◽  
Open Pit ◽  
Type I ◽  
Fracture Toughness Test ◽  
Rock Anisotropy

Abstract Mining activities in open pit and underground mines will always be associated with rock breaking or stripping activities (both mechanical and blasting), so that this can affect the structure and strength of rocks. The strength of the rock is strongly influenced by the presence of initial cracks (pre-existing cracks) and rock anisotropy conditions associated with discontinuous plane conditions. Fracture mechanics is a science that illustrates how a fracture can occur and propagate during applied stress on material. The main parameter in fracture mechanics is called fracture toughness which shows the resistance of the material to propagate the crack. There are several mode in determining type I fracture toughness, one of which is type I fracture toughness Flattened Brazilian Disc (FBD) mode. Type I fracture toughness test is carried out using a compression machine in a laboratory and is conducted on concrete samples consisting of 3 (three) various samples, with a ratio of cement and sand composition of 1:1, 1:2, and 2:1. This test also uses different loading rate values, namely 2.50 mm/min, 2.70 mm/min, and 2.83 mm/min. The results of the type I fracture toughness value from each loading rate will be compared to determine the effect of the loading rate on the value of type I fracture toughness. The obtained fracture toughness value is also related to the physical and mechanical properties of the samples. Based on the results of tests, it can be seen that the loading rate affects the value of fracture toughness, the increase in fracture toughness value is followed by the higher loading rate. In addition, it can be seen that the fracture toughness value is directly proportional to the uniaxial compressive strength value and the indirect tensile strength value. The average correlation value obtained is R2 = 0.9884 (indicating a strong relationship).

scholarly journals Design of Groundwater Sustain Irrigation Network System in Panca Lautang Area, Sidrap Regency, South Sulawesi

2021 ◽  
Vol 921 (1) ◽  
pp. 012084
Author(s):  
B Hidayah ◽  
A Jaya ◽  
A I D Puspita ◽  
B R M
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Loading Rate ◽  
Physical And Mechanical Properties ◽  
Strong Relationship ◽  
Open Pit ◽  
Type I ◽  
Fracture Toughness Test ◽  
Irrigation Network ◽  
Rock Anisotropy

Abstract Mining activities in open pit and underground mines will always be associated with rock breaking or stripping activities (both mechanical and blasting), so that this can affect the structure and strength of rocks. The strength of the rock is strongly influenced by the presence of initial cracks (pre-existing cracks) and rock anisotropy conditions associated with discontinuous plane conditions. Fracture mechanics is a science that illustrates how a fracture can occur and propagate during applied stress on material. The main parameter in fracture mechanics is called fracture toughness which shows the resistance of the material to propagate the crack. There are several mode in determining type I fracture toughness, one of which is type I fracture toughness Flattened Brazilian Disc (FBD) mode. Type I fracture toughness test is carried out using a compression machine in a laboratory and is conducted on concrete samples consisting of 3 (three) various samples, with a ratio of cement and sand composition of 1:1, 1:2, and 2:1. This test also uses different loading rate values, namely 2.50 mm/min, 2.70 mm/min, and 2.83 mm/min. The results of the type I fracture toughness value from each loading rate will be compared to determine the effect of the loading rate on the value of type I fracture toughness. The obtained fracture toughness value is also related to the physical and mechanical properties of the samples. Based on the results of tests, it can be seen that the loading rate affects the value of fracture toughness, the increase in fracture toughness value is followed by the higher loading rate. In addition, it can be seen that the fracture toughness value is directly proportional to the uniaxial compressive strength value and the indirect tensile strength value. The average correlation value obtained is R2 = 0.9884 (indicating a strong relationship).

Comparative Study of effectiveness of mobilization with movement (MWM) and End range mobilization (ERM) techniques in frozen shoulder

2018 ◽  
Vol 4 (4) ◽  
pp. 519-522
Author(s):  
Jeyakumar S ◽  
Jagatheesan Alagesan ◽  
T.S. Muthukumar
Keyword(s):  
Range Of Motion ◽  
Frozen Shoulder ◽  
Type I ◽  
Mean Values ◽  
Functional Activities ◽  
Group A ◽  
The Mean ◽  
Group B

Background: Frozen shoulder is disorder of the connective tissue that limits the normal Range of motion of the shoulder in diabetes, frozen shoulder is thought to be caused by changes to the collagen in the shoulder joint as a result of long term Hypoglycemia. Mobilization is a therapeutic movement of the joint. The goal is to restore normal joint motion and rhythm. The use of mobilization with movement for peripheral joints was developed by mulligan. This technique combines a sustained application of manual technique “gliding” force to the joint with concurrent physiologic motion of joint, either actively or passively. This study aims to find out the effects of mobilization with movement and end range mobilization in frozen shoulder in Type I diabetics. Materials and Methods: 30 subjects both male and female, suffering with shoulder pain and clinically diagnosed with frozen shoulder was recruited for the study and divided into two groups with 15 patients each based on convenient sampling method. Group A patients received mobilization with movement and Group B patients received end range mobilization for three weeks. The outcome measurements were SPADI, Functional hand to back scale, abduction range of motion using goniometer and VAS. Results: The mean values of all parameters showed significant differences in group A as compared to group B in terms of decreased pain, increased abduction range and other outcome measures. Conclusion: Based on the results it has been concluded that treating the type 1 diabetic patient with frozen shoulder, mobilization with movement exercise shows better results than end range mobilization in reducing pain and increase functional activities and mobility in frozen shoulder.

Experimental Investigation on Relative Crack Length For Fracture Toughness of Concrete

2010 ◽  
Vol 146-147 ◽  
pp. 1524-1528 ◽  
Author(s):  
Xue Zhi Wang ◽  
Zong Chao Xu ◽  
Zhong Bi ◽  
Hao Wang
Keyword(s):  
Fracture Toughness ◽  
Experimental Investigation ◽  
Crack Length ◽  
Fracture Toughness Test ◽  
Test Results ◽  
Toughness Test ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
Wedge Splitting

The wedge splitting test specimens with three series of different relative crack length were used to study the influences of relative crack length on the fracture toughness of common concrete. The suitable formulation for fracture toughness of concrete with different relative crack length was gotten on comparing between fracture toughness test results and computation results of the model developed from Hu formula.

scholarly journals A COMPARISON BETWEEN SYNTHETIC AND BIOSYNTHETIC MESHES IN THE SURGICAL TREATMENT OF SEVERE GENITAL PROLAPSE: RESULTS AND COMPLICATIONS

2010 ◽  
Vol 23 (3) ◽  
pp. 21
Author(s):  
S. Dati ◽  
V. De Lellis ◽  
P. Palermo ◽  
G. Carta
Keyword(s):  
Genital Prolapse ◽  
Pelvic Organ ◽  
Wilcoxon Test ◽  
Type I ◽  
Replacement Surgery ◽  
Group A ◽  
Group B ◽  
Work Up

The effectiveness, tolerability and complications of two surgical procedures using prosthetic materials with different physical and structural properties were assessed with a full Urogynecology work-up, through a retrospective study of 158 patients with severe genital prolapse (POP-Q staging III-IV) selected from November 2006 to April 2009. Eighty-six patients underwent fascial replacement surgery with ProliftTM System with a dual transobturator access in the anterior district and a transperineal posterior access with a synthetic polypropylene type I mesh (Group A). Seventy-two patients who underwent pelvic organ prolapse surgery with Avaulta/Avaulta PlusTM System with a dual transobturator access in the anterior district and a dual transperineal posterior access with a biosynthetic polypropylene type I mesh coated with a film of hydrophilic porcine collagen were placed in Group B. There were no intra and postoperative complications. Results of mean 20.8 month follow-up showed an effective anatomical cure rate of 89.5% in group A and 86.1% in group B and a low percentage of erosive complications, 8.1% and 5.6% respectively. Validated questionnaires for prolapse, the UDI 6 s.f., the IIQ7 s.f. and the PISQ-12 all showed a statistically significant improvement of quality of life in patients undergoing the two procedures (Wilcoxon test: P<0.001).

scholarly journals Maintenance treatment of diabetic patients, associating arterial obstructive tibio-peroneal disease

1995 ◽  
Vol 113 (1) ◽  
pp. 701-705
Author(s):  
Nelson Wolosker ◽  
Ruben Miguel Ayzin Rosoky ◽  
Baptista Muraco Neto ◽  
Berilo Langer
Keyword(s):  
Maintenance Treatment ◽  
Diabetic Patients ◽  
Type I ◽  
Group I ◽  
Significant Difference ◽  
Therapeutic Procedures ◽  
Arterial Pulsation ◽  
Group A ◽  
Group B ◽  
Better Than

When a melito-diabetic patient presents trophic infected injury on the limb, it is essential an evaluation of the circulatory conditions for therapeutic procedures orientation. In some circumstances, although arterial pulsation is absent, there is no ischemia of tissues. In these cases, the maintenance treatment, with eventual resection of the necrosed and infected tissues may be adopted. Evolution of 70 diabetic patients with trophic injuries on extremities were submitted to a maintenance treatment. Age of patients varied from 28 to 88 years, with an average of 56.8. The most occurrence was verified in women, with 42 cases. Diabetes non-dependant on insuline (type II) was observed in 64 patients (91.5%), being the remaining 6 patients of type I. Diabetic retinopathy was observed in 14 (20%) of the patients, neuropathy in 22 (31%) and nephropathy in 8 patients (11.4%). All the patients presented arterial pulsation until the popliteal region. They were divided in 2 groups, considering trunk arteries of legs: Group I, pervial legs arteries, composed by 48 patients; Group II, occluded legs arteries, with 22 patients. In what refers to the anatomic local of the injuries, patients were classified in three groups: Group A, formed by 32 patients (45.7%), presenting injuries in one or two toes only, without affecting the metatarsic region; Group B, formed by 16 patients (22.9%), trophic injuries affecting the metatarsic region and Group C, formed by 22 patients (31.4%), injuries affecting the calcaneous region. Injuries in both of the groups were caused by mechanical traumatism. Duration of the injury in the inferior member varied from 7 to 48 days, resulting in a 12 days average. Analyzing pervicacity in trunk arterias and evolution of patients, it may be observed that there has been a significantly better result in those with all the pulses present (81.3% x 45.5%)(p<0,01). Studying the injury locals associated to the evaluation of the cases, we may observe that for injuries in the extreme digital, result is significantly better than in locals more nearly. When distal pulses are absent, there is no significant difference in the result of the treatment, being performed in distal injuries or in the more near ones (p>0,05)(Table IV).

scholarly journals A Comparative Clinical Study of Trikarshika Kwatha with and without Lifestyle Modification in the Management of Vatarakta with Special Reference to Hyperuricaemia

2021 ◽  
pp. 10-19
Author(s):  
Md Tanzil Ansari ◽  
Sukumar Ghosh ◽  
Shailendra Kumar Singh
Keyword(s):  
Clinical Study ◽  
Lifestyle Modification ◽  
Test Results ◽  
Before And After ◽  
Comparative Clinical Study ◽  
Group A ◽  
Group B ◽  
High Level ◽  
Urate Crystals

Nowadays, people are more vulnerable to metabolic disorders due to their faulty dietary and behavioural habits. One such disorder is Vatarakta which causes functional impairment due to involvement of Sandhi (joints). It is manifested by Ruk, Toda, Sparsha asahatva, Shopha, Raga, Daha and Stabdhata in Sandhi. Vatarakta can be correlated with Hyperuricaemia or Gout due to similarity in their clinical features. Hyperuricaemia is defined as abnormally high level of uric acid in blood (i.e. >6mg/dl in female and >7mg/dl in male). On the other hand, Gout is an inflammatory response to monosodium urate crystals formed secondary to hyperuricaemia. Aims and objectives: 1. To evaluate the effectiveness of Trikarshika kwatha and lifestyle modification in the management of Vatarakta. 2. To compare the effects of Trikarshika kwatha with and without lifestyle modification in the management of Vatarakta. Materials and methods: Raw herbs of the research formulation were collected after proper identification and Kwatha was prepared for oral administration. For the clinical study, total 60 patients were selected on the basis of selection criteria. Selected patients were randomly divided into two groups. (i) Group A: 30 patients were treated with Trikarshika kwatha. (ii) Group B: 30 patients were treated with Trikarshika kwatha along with Lifestyle modification. Individual patient was treated for 45 days along with follow up at the interval of every 15 days. To assess the effectiveness of treatment, scoring pattern was followed for subjective and objective parameters. They were assessed before and after treatment. The collected data were analysed statistically by using Paired t-test. Results: On the basis of all statistical data, it can be said that patients of Group B showed better results in all parameters in comparison to patients of Group A. Conclusion: Both Trikarshika kwatha and Lifestyle modification are affective but Trikarshika kwatha with Lifestyle modification is more effective than Trikarshika kwatha without Lifestyle modification in the management of Vatarakta.

scholarly journals Influence of Ulnar Bow Sign on Surgical Treatment of Missed Bado Type I Monteggia Fracture in Children

2020 ◽  
Author(s):  
Shijie Liao ◽  
Tiantian Wang ◽  
Qian Huang ◽  
Yun Liu ◽  
Rongbin Lu ◽  
...  
Keyword(s):  
Surgical Treatment ◽  
Radial Head ◽  
Monteggia Fracture ◽  
Type I ◽  
Ulnar Osteotomy ◽  
Group A ◽  
The Mean ◽  
Group B ◽  
Stable Reduction

Abstract PurposeThe present study aimed to explore the influence of ulnar bow on the surgical treatment of Bado type I missed Monteggia fracture in children.MethodsThis study is a retrospective review of 24 patients between November 2010 and March 2019. All patients were treated with open reduction of the radial head and ulnar opening wedge osteotomy without annular ligament reconstruction. The mean interval between injury onset and surgery was five months (range: 2–12 months). The average age of participants at the time of surgery was 6.4 years (range: 3–10 years). We evaluated the maximum ulnar bow (MUB) and MUB position (P-MUB) via radiography. The patients were divided into middle group (group A: 14 cases, MUB located at 40% to 60% of the distal ulna) and distal group (group B: 10 cases, MUB located at 20% to 40% from the distal end of the ulna) based on P-MUB. The mean period of follow-up was 37 months (range: 6–102 months).ResultsAt the last follow-up, all the children showed stable reduction of the radial head, and the flexion function of elbow joint improved after operation (P<0.05). Group A presented a larger the ratio of maximum ulnar bow(R-MUB) and angle of ulnar osteotomy(OA) than group B (P<0.05). There was statistically significant difference between group A and Group B in the P-MUB (P < 0.05). The osteotomy angle was positively correlated with the R-MUB (R2 =0.497,P=0.013), The osteotomy angle was positively correlated with the P-MUB (R2=0.731,P=0.000), The R-MUB is proportional to the P-MUB (R2 =0.597,P=0.002). The regression equation of P-MUB and osteotomy angle: Angle=7.064+33.227* P-MUB (R2=0.459, P =0.000).ConclusionWhen the ulnar bow is positioned at the middle ulna, a stable reduction of radial head need to be achieved through a larger angle in the ulnar osteotomy. If the position of maximum ulnar bow (P-MUB) is closer to the middle of the ulna or the ratio of maximum ulnar bow (R-MUB) is larger, the osteotomy angle is larger.

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