Compacted nanosilica-talic/calcium carbonate polyacrylate composites prepared using accelerated sedimentation

The effectiveness of centrifugation as the compacting method in preparing high filler composites has been investigated. Different size and shape of fillers were used to ensure efficient filler space filling. In situ polymerization of bisphenol-A ethoxy diacrylate after centrifugating produced biomimetic composites with 74–86 % filler content. The filler space was efficiently filled by using a combination of nano and microsize fillers, especially in the nanosilica-CaCO3 composite. The morphology of the composites indicates that the fillers were well dispersed and embedded in the polymer matrix. The etched surface of the nanosilica-talc composite reveals that the combination of talc and nanosilica formed a biomimetic composite that displayed an ordered brick-and-mortar nacre-like structure. The wide-angle X-ray diffraction patterns indicate the crystal structure of CaCO3 and talc were maintained in the composit

Model Pembelajaran Kooperatif Tipe Stad (Student Teams Achievement Division) Dikombinasikan dengan Media Animasi pada Materi Laju Reaksi Kelas XI SMA Negeri 1 Palu

Students have difficulties in understanding chemistry subject contained mathematical calculation like on reaction rate topic. Cooperative learning model STAD type can be an alternative for the material contained calculation whereas animation media is for conceptual understanding. The objective of the research was to determine the influence of cooperative learning model STAD type combined with animation media for the eleventh grade students of SMA Negeri 1 Palu in academic year 2012/2013 toward the students' learning outcome on reaction rate material. This research was quasy experimental using posttest-only control group design. The population was the whole eleventh grade students of science program with the sample determination using purposive sampling method. The sample were class of science program 2 as the experimental class which using cooperative learning model STAD type with animation media whereas class of science program 4 as the control one which using convensional learning method. The research results showed that cooperative learning model STAD type combined with animation media at reaction rate material gave students' learning outcome higher than convensional method

Risk Factors for the Development of Knee Osteoarthritis

Objective. This article presents case control study conducted at the Rheumatology Outpatient Unit, Department of Internal Medicine, Cipto Mangunkusumo Hospital. The aim of this study was to determine several risk factors for the development of knee osteoarthritis (OA) at Rheumatology out-patient unit Department of InternalMedicine, Cipto Mangunkusumo Hospital.Method. This study used a case control design. Subjects were divided into two groups, case group and control group. The case group included all patients who had kneecomplaints that fulfi lled the 1990 American College of Radiology criteria while the control group included patients randomly chosen from visitors of the RheumatologyOutpatient Unit of Cipto Mangunkusumo Hospital who did not complain of knee pain and had been proven of not suffering OA by physical and radiological examinations. A similar questionnaire was designed for both groups. After filling out the questionnaire, both groups were examined physically and radiologically. The risk factors were analyzed using logistic regression.Results. We included 127 patients in the case group and 102 in the control group. In the case group, there were 95 women (74.80 %) and 32 men (25.20%) while the control group consisted of 69 women (67.65%) and 33 men (32.35%). From the analysis of several risk factors, there were signifi cant differences between the case and control groups such as weight (p < 0.0001 df 3), prior history of overweight or obesity (x2 = 21.255, df 1, p < 0.0001), knee trauma (p = 0.0002), and kneel down activity (p < 0.0001). There was also a signifi cant difference of smoking habit between the case group and the control group (p < 0.0001). Duration of smoking cessation was also signifi cantly different between the case group and controlgroup (t = 2.315, df 45, p = 0.0252). From the multivariate analysis, it was found that age, kneel down activity, prior obesity condition, interval between knee trauma and onset of OA, smoking habit, and duration of smoking cessation had a signifi cant correlation with knee OA.Conclusion. Age, prior history of overweight or obesity, kneeling, and interval between knee trauma and onset of OA were risk factors of knee OA. Smoking was a negative risk factor for knee OA. The protective effect of smoking was infl uenced by the duration of smoking habit and the duration of smoking cessation

Risk factors for the development of knee osteoarthritis

Objective. This article presents case control study conducted at the Rheumatology Outpatient Unit, Department of Internal Medicine, Cipto Mangunkusumo Hospital. The aim of this study was to determine several risk factors for the development of knee osteoarthritis (OA) at Rheumatology out-patient unit Department of InternalMedicine, Cipto Mangunkusumo Hospital.Method. This study used a case control design. Subjects were divided into two groups, case group and control group. The case group included all patients who had kneecomplaints that fulfi lled the 1990 American College of Radiology criteria while the control group included patients randomly chosen from visitors of the RheumatologyOutpatient Unit of Cipto Mangunkusumo Hospital who did not complain of knee pain and had been proven of not suffering OA by physical and radiological examinations. A similar questionnaire was designed for both groups. After filling out the questionnaire, both groups were examined physically and radiologically. The risk factors were analyzed using logistic regression.Results. We included 127 patients in the case group and 102 in the control group. In the case group, there were 95 women (74.80 %) and 32 men (25.20%) while the control group consisted of 69 women (67.65%) and 33 men (32.35%). From the analysis of several risk factors, there were signifi cant differences between the case and control groups such as weight (p &lt; 0.0001 df 3), prior history of overweight or obesity (x2 = 21.255, df 1, p &lt; 0.0001), knee trauma (p = 0.0002), and kneel down activity (p &lt; 0.0001). There was also a signifi cant difference of smoking habit between the case group and the control group (p &lt; 0.0001). Duration of smoking cessation was also signifi cantly different between the case group and controlgroup (t = 2.315, df 45, p = 0.0252). From the multivariate analysis, it was found that age, kneel down activity, prior obesity condition, interval between knee trauma and onset of OA, smoking habit, and duration of smoking cessation had a signifi cant correlation with knee OA.Conclusion. Age, prior history of overweight or obesity, kneeling, and interval between knee trauma and onset of OA were risk factors of knee OA. Smoking was a negative risk factor for knee OA. The protective effect of smoking was infl uenced by the duration of smoking habit and the duration of smoking cessation

Study of the Effect of WO3 and Bi2O3 on the Microstructure and Electrical Properties of A TiO2 based Varistor

Titanium dioxide (TiO2) varistors doped with tungsten oxide (WO3) and bismuth oxide (Bi2O3) were investigated. The microstructure and electrical characterization were studied, where the effects of different concentrations of WO3 and a fixed amount of Bi2O3 were investigated. TiO2 based varistors have promising potential for the high performance development. The percentage of dopant was varied at various levels and the prepared samples were then characterized by evaluating IV relationships to determine the degree of non-linearity in the varistor. Evaluation was conducted based on non-linear coefficients, breakdown voltage and power loss. Microstructure analysis was also carried out using SEM. The average grain size was determined to find the relationship between microstructure and electrical properties. It was found that a molar concentration with 99.1%TiO2. 0.4%WO3. 0.5%Bi2O3 yielded the best results in terms of electrical and microstructural properties. The addition of 0.5%Bi2O3 and 0.4%WO3 creates a relatively low clamping efficiency, higher non-linear coefficient, low breakdown voltage and less power loss

Preparation and Characterization Of Untreated Waste Palm Oil/Diesel Fuel Blend

Some diesel engines can run on some kinds of vegetable oil under some conditions without problems. To use vegetable oils in diesel engine without modification, it is necessary to make sure that the vegetable oils properties must be similar to diesel fuel. In this study, palm oil that has been used several times for frying purposes is investigated for the utilization as an alternative fuel for diesel engines. The waste palm oil has a variety of qualities, possess properties different from that of neat oils. Higher impurities of the used oils make them different from neat vegetable oil. The high viscosity of the waste palm oil was decreased by blending with diesel. Two different previous uses of waste palm oil were blend with diesel. The blends of varying proportions of waste palm oil and diesel were prepared, analyzed and compared with diesel fuel and the waste palm oil ethyl ester. The properties of the blends such as heating value, viscosity, specific gravity, etc. were determined. It was found that blending waste palm oil with diesel reduces the viscosity and different previous uses of waste palm oil significantly affected the properties of the blended fuels. From the properties test results it has been established that blends containing 5 to 40% of waste palm oil in diesel yielded the properties closely matching that of diesel

Effect of dental implant micro-thread designs on stress distribution in bone-implant interface

Dental implants have been used in replacing broken or damaged teeth. There are failures after the operation was done due to lack of primary stability. Through improving the design of the dental implant, primary stability can be achieved. The aim of the study is to analyse the stress distribution at bone-implant interface due to different micro-thread designs. Five types of two-dimension micro-thread shapes dental implant embedded in bone cube are modeled in ANSYS APDL R3. The micro-thread shapes are Straight, Square, V-shaped, Buttress and Reverse Buttress. The models are meshed using element Quad 8-node 183. 106.066N of horizontal force and vertical force are applied on each model to find out the stress distribution pattern and peak Von Mises stress. The study found that micro-thread shapes changed the stress distribution on implant and bone. The peak Von Mises stress was located at the first micro-thread. Cortical bone took large portion of stress compared to cancellous bone. Square micro-thread has the best stress distribution pattern

The transmission of trauma in refugee families: associations between intra-family trauma communication style, children’s attachment security and psychosocial adjustment

This study explores the transmission of trauma in 30 Middle Eastern refugee families in Denmark, where one or both parents were referred for treatment of PTSD symptoms and had non-traumatized children aged 4–9 years. The aim of the study was to explore potential risk and protective factors by examining the association between intra-family communication style regarding the parents’ traumatic experiences from the past, children’s psychosocial adjustment and attachment security. A negative impact of parental trauma on children might be indicated, as children’s Total Difficulties Scores on the Strengths and Difficulties Questionnaire (SDQ) were significantly higher than the Danish norms. A negative association between children’s attachment security as measured by the Attachment and Traumatization Story Task and higher scores on the SDQ Total Difficulties Scale approached significance, suggesting that the transmission of trauma may be associated with disruptions in children’s attachment representations. Furthermore a significant association between parental trauma communication and children’s attachment style was found