76 research outputs found

    The effect of adding natural materials waste on the mechanical properties and water absorption of epoxy composite using grey relations analysis

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    Recently, there has been a tendency for scientific studies to deal with natural materials as fillers and reinforcement for polymer composites, which are used in many different applications due to their environmentally friendly properties when compared to synthetic materials. The current study aims to preserve the environment by dealing with natural materials and their influence on the mechanical properties and water absorption property of the polymer composites. In this study, epoxy composites were produced from local natural sourced non-hazardous raw natural materials using grey relational analysis (GRG). The materials used for fabrication include micro-filler of pollen palm 50 μm, seashell 75 μm and epoxy resin. Nine different composites were prepared using pollen palm and seashell as reinforcement material by varying the wt % of the micro-filler. Rule of the mixture was used for formulation and wt % of (0.5, 1 and 1.5) % reinforcement and 99.5, 99 and 98.5 % epoxy (binder) were used for composites. Grey relational analysis was conducted in order to scale the multi-response performance to a single response. The results indicate that optimum performance can be achieved with the addition of 1.5 wt % micro-filler of seashell, which achieved the first rank, while the second rank achieved by 0.5 wt % micro-filler of palm pollen and seashell when compared to other composites. The addition of micro-fillers has improved greatly the mechanical properties of epoxy composites. The loading of micro-fillers has influenced the water absorption property of composites based epoxy in ascending orde

    The Impact of Website Quality on Online Purchase Intention: The Mediating Effect of e-WOM, Jordan Context

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    Purpose: The objective of the study is to investigate how the quality of a website impacts the intent to purchase, as assessed by factors such as usability, quality of information, service interaction quality, eWOM, trust, and satisfaction.   Theoretical framework: This research has provided empirical evidence of the factors that influence the online shopping behavior of consumers.   Design/methodology/approach: The research was conducted using a quantitative approach, with SPSS statistical methods applied. An online survey was administered to 303 customers in Amman, the capital of Jordan.   Findings: The results suggest that website quality, customer trust, and satisfaction significantly and positively impact eWOM, thereby increasing the intent to purchase among consumers in Jordan's e-commerce sector.   Research, Practical & Social implications: This research offers valuable managerial principles to assist e-commerce businesses in improving their performance. It also provides valuable insights into the evaluation of eWOM and purchases intent in Jordan, serving as a foundation for future research in this area in Jordan and other countries.   Originality/value: this study provides a foundation for future research to investigate the complex and multifaceted nature of online customer behaviour in the e-commerce contex

    Sponge media drying using a swirling fluidized bed dryer

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    Surface preparation today has seen the introduction of sponge media as an alternative product against the traditionally used abrasive materials. Being soft and elastic, the sponge media reduces air borne emission significantly during surface preparation with capability to be re-used. However the environmental conditions limit the sponge media usage whereby wet surroundings prohibit the re-use of the sponge without being dried properly. This study proposes the swirling fluidized bed dryer as a novel drying technique for sponge media. Batch experiments were conducted to study the bed’s hydrodynamics followed by drying studies for three bed loadings of 0.5 kg, 0.75 kg and 1.0 kg at three drying temperatures of 80°C, 90°C and 100°C. It was found that, minimum fluidization velocities for the wet sponge particles were found to be 1.342, 1.361 and 1.382 m/s with minimum swirling velocities of 1.400, 1.469 and 1.526 m/s. Drying times were recorded between 6 to 16 minutes depending on bed loading and drying temperature. Smaller bed weights exhibits faster drying with constant-rate drying period while higher drying temperature and larger bed load resulted in falling-rate drying period. Thin layer modelling for the falling-rate region indicates that Verma et. al model provides the best fit for the present experimental data with coefficient of determination, R2 = 0.98773, root mean square error, RMSE = 0.05048, residuals = 0.3442 and reduced chi-square, χ2 = 0.00254. The effective diffusivity, Deff, for 0.5 kg bed load was found to be 3.454 x 10-9 m2/s and 1.751 x 10-9 m2/s for 0.75 kg bed load. In conclusion, SFBD was found to be a viable and efficient method in drying of sponge media for various industrial applications particularly surface preparation

    Evaluation of safety, efficacy and pharmacokinetics of Eltrombopag in patients with chronic immune thrombocytopenia: Meta-analysis of randomized controlled trials

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    The present meta-analysis is to evaluate the safety and efficiency of Eltrombopag in the prevention and therapy of Immune thrombocytopeni

    The auto assist bar system for disabled people

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    This paper presents the development of the auto assist bar system to help the disabled people especially paralyzed in the legs where they have a problem to doing transaction stand-to-sit and sit-to-stand. An example the difficult movement of people with disabilities are from wheelchair to bed or from wheelchair to the toilet bowl. Many people with disabilities use the grab bars or assist bar are sold in the markets where it is too difficult and require a lot of energy to use which can cause them to fall and injured. Through this system, the disabled people can do the transaction stand-to-sit and sit-to-stand without assistance from other persons. The work will be performed during this project is testing performance of the sensors, design for the entire system either on mechanical parts and use the PID controller by using Arduino to control of dc motor. PID parameter values of Kp, Ki and Kd is obtained which is suitable to enable a dc motor rotates smoothly. The overall results obtained from this project found all managed to achieve the overall objectives of the system where the system is able to support people with disabilities to stand up and sit down

    An adaptive protection of flooding attacks model for complex network environments

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    Currently, online organizational resources and assets are potential targets of several types of attack, the most common being flooding attacks. We consider the Distributed Denial of Service (DDoS) as the most dangerous type of flooding attack that could target those resources. The DDoS attack consumes network available resources such as bandwidth, processing power, and memory, thereby limiting or withholding accessibility to users. The Flash Crowd (FC) is quite similar to the DDoS attack whereby many legitimate users concurrently access a particular service, the number of which results in the denial of service. Researchers have proposed many different models to eliminate the risk of DDoS attacks, but only few efforts have been made to differentiate it from FC flooding as FC flooding also causes the denial of service and usually misleads the detection of the DDoS attacks. In this paper, an adaptive agent-based model, known as an Adaptive Protection of Flooding Attacks (APFA) model, is proposed to protect the Network Application Layer (NAL) against DDoS flooding attacks and FC flooding traffics. The APFA model, with the aid of an adaptive analyst agent, distinguishes between DDoS and FC abnormal traffics. It then separates DDoS botnet from Demons and Zombies to apply suitable attack handling methodology. There are three parameters on which the agent relies, normal traffic intensity, traffic attack behavior, and IP address history log, to decide on the operation of two traffic filters. We test and evaluate the APFA model via a simulation system using CIDDS as a standard dataset. The model successfully adapts to the simulated attack scenarios' changes and determines 303,024 request conditions for the tested 135,583 IP addresses. It achieves an accuracy of 0.9964, a precision of 0.9962, and a sensitivity of 0.9996, and outperforms three tested similar models. In addition, the APFA model contributes to identifying and handling the actual trigger of DDoS attack and differentiates it from FC flooding, which is rarely implemented in one model

    Bone Substitutes in Management of Benign Bone Tumors, Review of Literature

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    Intralesional excision or curettage is commonly used to treat benign and low-grade malignant bone tumors. The resulting defect can be treated with a variety of materials, such as autologous bone grafts, allografts, or synthetic materials like polymethylmethacrylate or composite alternatives. Because it is osteogenic, osteoinductive, and osteoconductive, autologous cancellous bone is often considered the gold standard of transplant material. However, issues including transplant size limitations, wound-related complications, and prolonged donor site pain have limited its usage in clinical practice. Concerns about immunogenicity and infection have also hampered the use of demineralized freeze-dried allografts and xenografts.  As a result, synthetic materials have sparked substantial interest in orthopedics, and a variety of bone graft alternatives are now commercially accessible

    Melatonin ameliorates serobiochemical alterations and restores the cardio-nephro diabetic vascular and cellular alterations in streptozotocin-induced diabetic rats

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    Melatonin possesses a wide range of pharmacological activities, including antidiabetic properties. Diabetes mellitus (DM) induces several physiopathological changes in body organs, which could be observed lately after systemic failure. In the current study, we aimed to investigate the serobiochemical changes and the histopathological picture in the diabetic heart and the kidney early before chronic complications and highlight the association between hyperglycemia, glomerular alterations, and cardiovascular changes. In addition, the role of melatonin in the treatment of cardio-nephro diabetic vascular and cellular adverse changes in streptozotocin-induced diabetic rats was also studied. A total of 40 mature Wistar albino rats were distributed into five groups; (1) control untreated rats, (2) diabetic mellitus untreated (DM) rats, in which DM was induced by the injection of streptozotocin (STZ), (3) control melatonin-treated (MLT), (4) melatonin-treated diabetic (DM + MLT) rats, in which melatonin was injected (10 mg/kg/day, i.p.) for 4 weeks, and (5) insulin-treated diabetic (DM + INS) rats. The serum biochemical analysis of diabetic STZ rats showed a significant (P < 0.05) increase in the concentrations of blood glucose, total oxidative capacity (TOC), CK-MB, endothelin-1, myoglobin, H-FABP, ALT, AST, urea, and creatinine as compared to control rats. In contrast, there was a significant (P < 0.05) decrease in serum concentration of insulin, total antioxidative capacity (TAC), total nitric oxide (TNO), and total protein level in DM rats vs. the control rats. Significant improvement in the serobiochemical parameters was noticed in both (DM + MLT) and (DM + INS) groups as compared with (DM) rats. The histological examination of the DM group revealed a disorder of myofibers, cardiomyocyte nuclei, and an increase in connective tissue deposits in between cardiac tissues. Severe congestion and dilation of blood capillaries between cardiac muscle fibers were also observed. The nephropathic changes in DM rats revealed various deteriorations in glomeruli and renal tubular cells of the same group. In addition, vascular alterations in the arcuate artery at the corticomedullary junction and interstitial congestion take place. Melatonin administration repaired all these histopathological alterations to near-control levels. The study concluded that melatonin could be an effective therapeutic molecule for restoring serobiochemical and tissue histopathological alterations during diabetes mellitus
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