Effect of Fly Ash Fraction and Mixing Process Variables On Mechanical Properties of Polymer Composites

The development of material technology continues to be carried out to meet the needs of engineering materials which are increasing day by day and are environmentally friendly or green. In this study, the process of making epoxy resin composites with fly ash was carried out from the combustion process of a power plant. This study aims to determine the strength of the mechanical properties between the epoxy resin and fly ash weight fraction by stirring treatment in the mixing process using tensile, flexural, and impact tests, microscopic examination, FTIR, and X-RD analysis. The treatments were mixing epoxy resin and fly ash with a weight fraction of 10%, 20%, and 30%, stirring speeds of 100 rpm, 150 rpm, and 200 rpm, for 10 minutes, 20 minutes, and 30 minutes. The results showed that the F2S3T3 composite had a greater tensile strength of 31,94 MPa, while the other composites had a tensile strength above 22-30 MPa, and the lowest was 13,07 MPa in the F1S2T3 composite. The maximum modulus of elasticity is found in the F3S3T1 composite with a value of 11,12 MPa, and the lowest is found in the F1S2T3 composite at 2,06 MPa. The F3S2T2 composite has a maximum flexural strength of 33,32 MPa, and the lowest composite F2S2T1 is 17,40 MPa with a flexural modulus of 270,41 MPa. The maximum flexural modulus in the F1S1T1 composite with a value of 382,76 MPa with a flexural strength value of 28,82 MPa. The F2S1T2 composite has an impact energy of 6,94 Joules with an impact strength of 203,47 MPa, and there are 2 composites that have the same impact energy value of 5,20 Joules, namely F3S2T2, and F3S1T3. From SEM observations, the fracture surface of the composite has a concave and prominent surface, but a lot of dust is trapped so it affects the bond in the matrix and reinforcement

Effect of Fly Ash Fraction and Mixing Process Variables On Mechanical Properties of Polymer Composites

The development of material technology continues to be carried out to meet the needs of engineering materials which are increasing day by day and are environmentally friendly or green. In this study, the process of making epoxy resin composites with fly ash was carried out from the combustion process of a power plant. This study aims to determine the strength of the mechanical properties between the epoxy resin and fly ash weight fraction by stirring treatment in the mixing process using tensile, flexural, and impact tests, microscopic examination, FTIR, and X-RD analysis. The treatments were mixing epoxy resin and fly ash with a weight fraction of 10%, 20%, and 30%, stirring speeds of 100 rpm, 150 rpm, and 200 rpm, for 10 minutes, 20 minutes, and 30 minutes. The results showed that the F2S3T3 composite had a greater tensile strength of 31,94 MPa, while the other composites had a tensile strength above 22-30 MPa, and the lowest was 13,07 MPa in the F1S2T3 composite. The maximum modulus of elasticity is found in the F3S3T1 composite with a value of 11,12 MPa, and the lowest is found in the F1S2T3 composite at 2,06 MPa. The F3S2T2 composite has a maximum flexural strength of 33,32 MPa, and the lowest composite F2S2T1 is 17,40 MPa with a flexural modulus of 270,41 MPa. The maximum flexural modulus in the F1S1T1 composite with a value of 382,76 MPa with a flexural strength value of 28,82 MPa. The F2S1T2 composite has an impact energy of 6,94 Joules with an impact strength of 203,47 MPa, and there are 2 composites that have the same impact energy value of 5,20 Joules, namely F3S2T2, and F3S1T3. From SEM observations, the fracture surface of the composite has a concave and prominent surface, but a lot of dust is trapped so it affects the bond in the matrix and reinforcement

Transperitoneal laparoscopic pyeloplasty in children and adolescents: Long-term results

Background Open pyeloplasty has been the gold standard for the treatment of  ureteropelvic junction obstruction (UPJO) in children and young adolescents. However, the use of laparoscopy for the treatment of pyeloplasty is increasing as it has the potential to provide a better and more desirable cosmetic outcome in  addition to less postoperative pain and decreased recovery time. The aim of this study was to evaluate the long-term outcome of transperitoneal laparoscopic  pyeloplasty (TLP) for the treatment of UPJO in children and young adolescents.Patients and methods Twenty-nine patients with UPJO with 32 renal units were subjected to TLP at Al-Azhar University Hospitals, Egypt, during the period from May 2008 to December 2012. The outcome measurements of this study included operative time, internal stent placement, hospital stay, intraoperative complications, and success rates. Success is defined as both symptomatic relief and radiographic resolution of hydronephrosis at the last follow-up. Patients were followed up with intravenous urography and diethylene triamine penta-acetic acid scan at 3, 6, and 12 months regularly for both functional and morphological outcomes.Results The study included 29 patients (12 male and 17female) with 32 obstructed renal units. The mean age was  4.23 ± 2.1 years (range 3–16 years). All procedures were completed laparoscopically without conversion. The mean operative time was 143.41 ±23 min (range 110–220 min). The mean postoperative hospital stay was 4.1 days (range 3–8 days). All patients achieved full recovery without any complications. The mean follow-up period of the patients was 36.34± 5.18 months (range 22–60 months). Success rate was 96.9%. Only one case developed  recurrent UPJO and was treated with retrograde endopyelotomy and stenting.Conclusion TLP has the advantages of less postoperative pain, short hospital stay, and rapid recovery, with excellent functional and cosmetic outcomes. However, it requires advanced skill level for intracorporeal suturing and knot tying.Keywords: children, laparoscopy, long-term results, pyeloplasty, ureteropelvic junction obstructio

Comparative Computational Study of Mechanical Behavior in Self-Expanding Femoropopliteal Stents

The use of the stent to treat peripheral artery disease (PAD) is increased and the proportion of failures also increases. The femoropopliteal artery (FPA) experiences a high deformation ratio compared to the cardiovascular artery due to limp flexion and daily activities that could lead to stent failure, as well as increasing the number of observed mortality and morbidity. In the present work, two of the common PAD stent design models represented as STENT I and STENT II were analyzed by using of finite element method (FEM) to simulate the most mechanical loading modes that could occur in FPA, such as axial tension and compression, torsion, three-point bending and radial compression to give a good understanding of deformation that affected stent inside the in-vivo. The gradual force load was used to simulate all modes, the force values are 0.25 N, 0.5 N, 1.5 N, 2.5 N, 3.5 N and 5.5 N until the stent models obtain the yield-point. The comparison of stent models (STENT I, STENT II) was performed in terms of graphs of total deformation, force-stress and stress-strain for all test modes. The similarity ratio of the total deformation in axial tension and the compression mode for STENT I and STENT II was 17% and that may indicate that STENT I obtained a high deformation value instead of STENT II, while, the torsion similarity ratio was 86% which could show a good agreement in this mode, as well as the similarity ratio, was 78% of the total three-point bending deformation and the value of the similarity ratio in the radial compression mode was 23%. Still unclear what is the clinical mode of mechanical deformation that is more important than others with changing the length of the lesion and stent diameter, and the fatigue life test provides a better understanding of the mechanical tests that must be sought

Living kidney donation among ethnic minorities: A Dutch qualitative study on attitudes, communication, knowledge and needs of kidney patients

Background: Terminal kidney patients are faced with lower quality of life during dialysis treatment, restricted diets and high morbidity and mortality rates while waiting for a deceased donor kidney transplantation. Fortunately, living donor kidney transplantation offers an alternative with considerable advantages in terms of waiting time and graft survival rates. Nevertheless, we observed an inequality in the proportion of living kidney transplantations performed between the non-European patients and the European patients in our centre. To date little is known about the factors contributing towards this racial disparity. Previous research from our centre did not find any medical reasons to explain this racial disparity. We believe that non-medical psychosocial and cultural factors predominantly account for this discrepancy. Purpose Focus group discussions and in-depth interviews were conducted in order to gain insight in the attitudes, (non-)communication and knowledge of our non-European patients (compared to European patients) regarding living donor kidney transplantation (LDKT). Additionally, we investigated their attitudes towards professional support in finding an eligible living donor. Methods: The interviews were held in line with the focus group method and analyzed according to the grounded theory. The interviews were focused on six main topics (kidney transplantation, living kidney donation, communication, information, knowledge and intervention needs). European patients were included as a comparison group. The qualitative data analyses were performed in Atlas.ti. Results:We found nearly all our patient to be in favour of a living kidney transplantation (96%). However multiple prohibiting intertwined factors play a role when actually considering a living donor. We found four major barriers to the living donor transplantation process in our non-European patients: 1) not (so easily) comprehensible non-patient-centered information 2) cognitions and emotions (based on fears, concerns and misconceptions) 3) a state of basically non-communication with the potential donor(s) on this issue (as a consequence of personal and cultural beliefs) 4) and social influences. We also found some similar factors playing a role in the donation course of our European patients without a living donor. Finally, our patients held a welcoming attitude towards an intervention aimed at assisting them getting though the living donation program. Discussion: This study has identified several modifiable determinants underlying racial disparity in our living donor kidney transplantation program and investigated patients’ attitude towards two interventions aimed at alleviating this inequality. We realize that our list of barriers may not be thorough enough and surely more is to be said on this topic, the findings offer possible targets for intervention. In accordance with our patients’ preference, we argue that a home-based educatio

Multisystemic engagement & nephrology based educational intervention: A randomized controlled trial protocol on the kidney team at home-study

Background: Living donor kidney transplantation (LDKT) is the most successful form of renal replacement therapy in terms of wait time and survival rates. However, we observed a significant inequality in the number of LDKT performed between the Dutch and the non-Dutch patients. The objective of this study is to adapt, implement and test an educational home-based intervention to contribute to the reduction of this inequality. Our aim is to establish this through guided communication together with the social network of the patients in an attempt that well-informed decisions regarding renal replacement therapy can be made: Multisystemic Engagement & Nephrology. This manuscript is a detailed description of the Kidney Team At Home-study protocol. Methods and design. All patients (>18 yrs) that are referred to the pre-transplantation outpatient clinic are eligible to participate in the study. Patients will be randomly assigned to either an experimental or a control group. The control group will continue to receive standard care. The experimental group will receive standard care plus a home-based educational intervention. The intervention consists of two sessions at the patient's home, an initial session with the patient and a second session for which individuals from their social network are invited to take part. Based on the literature and behavioural change theories we hypothesize that reducing hurdles in knowledge, risk perception, subjective norm, self-efficacy, and communication contribute to well-informed decision making and reducing inequality in accessing LDKT programs. A change in these factors is consequently our primary outcome-measure. Based on power calculations, we aim to include 160 patients over a period of two years. Discussion. If we are able to show that this home-based group educational intervention contributes to 1) achieving well-informed decision regarding treatment and 2) reducing the inequality in LDKT, the quality of life of patients will be improved while healthcare costs are reduced. As the intervention is investigated in a random heterogeneous patient group in daily practice, the transfer to clinical practice in other kidney transplant centers should be relatively easy

Exploring Knowledge About Dialysis, Transplantation, and Living Donation Among Patients and Their Living Kidney Donors

Background: In order to make a well-considered decision and give informed consent about renal replacement therapy, potential living kidney donors and recipients should have sufficient understanding of the options and risks. Purpose: We aimed to explore knowledge about Dialysis & Transplantation (DT) and Living Donation (LD) among prospective living kidney donors and recipients. Methods: Eighty-five donors and 81 recipients completed the Rotterdam Renal Replacement Knowledge-Test (R3K-T) 1 day before surgery. The questionnaire was available in various languages. Results: Recipients knew significantly more about DT than donors (p < 0.001); donors knew more about LD than recipients (p < 0.001). A minority of donors (15 %) and recipients (17 %) had a score that was comparable to the knowledge level of the naïve general population. Recipients and donors knew less about DT and LD if their native language was not Dutch. In addition, recipients knew less about DT if they were undergoing pre-emptive transplantation. Conclusions: We conclude that recipients and donors retain different information. The decision to undergo living donation appears to be not always based on full knowledge of the risks. We recommend that professionals assess knowledge of prospective donors and recipients during the education process using the R3K-T, and extra attention is required for non-native speakers

Electrical discharge machining of polycrystalline diamond using copper electrode – finishing condition

Research on machining process of Polycrystalline Diamond (PCD) is becoming important as the material was believed suitable to be used for cutting tools of advanced aeronautical structure. Electrical Discharge Machining (EDM) was regarded as the suitable method to machine PCD due its noncontact process nature. The objective of this research is to determine the influence of several EDM parameter such as sparking current, pulse duration, and pulse interval to the material removal rate and surface roughness of the machined PCD. Instead of significantly influenced the material removal rate, the sparking current was also highly influenced tha surface roughness. Highest material removal rate of approximately 0.005mm3/s was recorded by the EDM process with the highest current used of 5A, and lowest pulse interval of 1µs. The influence of pulse duration is not clearly seen at the lowest pulse interval used. On the other hand, 0.4µm was the lowest surface roughness value obtained in this research indicated by the highest sparking current, highest sparking duration and lowest sparking interval of 5A, 1µs and 1µs respectively

Development of the Rotterdam Renal Replacement Knowledge-Test (R3K-T)

Introduction: There is currently a lack of validated or standardized measures to test the level of knowledge among renal patients regarding kidney disease and available treatment options. We conducted a pilot study to develop a questionnaire measuring knowledge of kidney disease, dialysis and transplantation options. The main aim of this study was to develop such an instrument for further use in research and practice. Method: An initial 61 item pool was generating by searching the literature and consulting experts in this area for additional items. This questionnaire was completed by 182 renal disease patients from 4 dialysis centers in the Rotterdam municipality. A factor analysis was conducted using the maximum likelihood factor method followed by direct oblimin rotation to obtain variance explained by each factor. Questions that loaded ≥ .30 on a factor were included. Results: Twenty-seven patients (24%) were in the pre-RRT phase, 60 (54%) were undergoing haemodialysis, 16 (14%) were undergoing peritoneal dialysis, and 9 (8%) had a graft failure. Forty (36%) were female and 72 (64%) were male. Age range 19-87 (median = 59). A factor analys

Electrical discharge machining of polycrystalline diamond using copper electrode – finishing condition

Research on machining process of Polycrystalline Diamond (PCD) is becoming important as the material was believed suitable to be used for cutting tools of advanced aeronautical structure. Electrical Discharge Machining (EDM) was regarded as the suitable method to machine PCD due its noncontact process nature. The objective of this research is to determine the influence of several EDM parameter such as sparking current, pulse duration, and pulse interval to the material removal rate and surface roughness of the machined PCD. Instead of significantly influenced the material removal rate, the sparking current was also highly influenced tha surface roughness. Highest material removal rate of approximately 0.005mm3/s was recorded by the EDM process with the highest current used of 5A, and lowest pulse interval of 1µs. The influence of pulse duration is not clearly seen at the lowest pulse interval used. On the other hand, 0.4µm was the lowest surface roughness value obtained in this research indicated by the highest sparking current, highest sparking duration and lowest sparking interval of 5A, 1µs and 1µs respectively