Optimization of injection molding parameter in processing polypropylene using Taguchi method / Mohamad Adib Adam Abd Wahab

Nowadays, manufacturing industry is growing rapidly in any country over the world. Plastic industry is the one of the manufacturing industry that has high demand products to consumers. Polypropylene is popular due to its characteristics such as recycle, low cost, chemical resistance, excellent impact strength, food grade availability and so on. The plastic product were produced by using injection molding machine at different injection molding parameters. The quality of product depends on the optimization of the injection molding parameter that will be set for producing plastic product. Thus, the optimization of the injection molding parameter on processing polypropylene by using design of experiment is the main objective of the study. The shrinkage and cycle time fabrication of polypropylene were investigated. Shrinkage is inherent in the injection molding process. This is because the density of polymer was different from the processing temperatures compared to the ambient temperature. The best value of injection molding parameters such as melting temperature, injection pressure, injection speed, cooling time, holding time and holding pressure have been obtained and optimized. From the results obtained, the most significant injection molding parameter on shrinkage and cycle time fabrication of polypropylene is holding time. The result has been supported by analysis of variance (Anova). By using design of experiment method, it has eliminate the trial and error method and save time and money in development and processing the plastic product. The optimization of injection molding parameter contributes to the plastic processing such as increasing productivity, quality and reliability of the product. The surface morphology of specimen hard to see because the polypropylene is semi crystalline polymer

Glass-formation region of ternary Sn-Sb-Se-based chalcogenide glasses

Tin-antimony-selenium (TAS)-based system belongs to the ternary chalcogenide compounds of IV-V-VI group owing to their heavy elemental masses, their glass formation region was assumed to be small comparing to their counterpart elements in the same group. However, there were rare published reports on their glass structure, while their glass boundary formation region was not yet reported. It was the aim of this paper to map their glass-forming region experimentally using XRD and validate it theoretically using the average co-ordination number, μ, and the fraction of the bond distributions, f, from chemical order model. Theoretically, it was validated that the glass formation was arrested between μ ≤ 2.4 and the fraction of Sn-Se bonds, f sn-se < 44.5%. XRD analyses of 66-as-prepared samples revealed that the glass formation region was located within the predicted area that mapped in structural triangle

A framework for design, modeling, and identification of compliant biomimetic swimmers

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 121-126).Research interests in fish-like devices are generally driven by the notion that through eons of evolution fish have developed optimal mechanisms for efficient propulsion and high degrees of maneuverability. Engineered fish-like devices have been developed in hope of mimicking the capabilities of their biological counterparts, but success has been marginal. This thesis considers a unique class of underactuated biomimetic swimmers with compliant bodies that swim by exploiting their structural dynamics. Practical matters surrounding the design and modeling of these swimmers are addressed and explicit references are made to fish morphology and swimming behaviours with the aim of linking biological and engineering design elements, a deficiency in existing literature. A hybrid modeling scheme is presented drawing upon conventional engineering primitives and experimental data. Both a hardware prototype swimmer and a unique motion capture system were developed to demonstrate the described methods. Experimental and simulated results are compared.by Adam Joseph Wahab.S.M

A nano-stepping robotic instrumentation platform

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 115-118).The development of an Autonomous Nano-stepping Tool (ANT) system is presented. Each ANT is a small, tripodal, robotic instrument capable of untethered precision motion within a quasi-three-dimensional workspace of arbitrary size. The project aimed to address limitations of conventional benchtop micro/nanoscale measurement and manipulation systems by offering a low-cost, scalable alternative with comparable performance and extended functionality and flexibility. The design, fabrication, and evaluation the various electrical, mechanical, and software subsystems are discussed. Device prototypes are introduced along with a platform-agnostic interface for remote monitoring and control. The device step size and its frequency dependence are examined. A novel, high-resolution capacitive probe concept is detailed and characterized as an example of an inexpensive, low-power, sensor technology with which an ANT may be equipped to perform scanning probe microscopy. Several positioning schemes are discussed, including a distributed vision-based approach which utilized a custom cross-correlation processor.by Adam Joseph Wahab.Ph. D

Duplex ultrasound for evaluation of deep venous blood flow in fractured lower extremities

Purpose: Early identification of deep venous thrombosis (DVT) in trauma patients would result in an early initiation of treatment, thereby decreasing the frequency of complications. The aim of the current study was to evaluate the role of duplex ultrasound (DUS) in the evaluation of deep venous blood flow in fractured lower extremities to rule out DVT prior to orthopedic surgery. Material and methods: In this prospective study a total of 58 patients (42 males and 16 females; mean age of 51.5 ± 19.5 years) with fractured lower extremities were thoroughly evaluated prior to surgery with respect to medical history, fracture pattern, associated injuries, comorbid conditions, and venous duplex ultrasound (VDUS) findings. Each affected limb was assessed for the presence of DVT using a Sonoline G 60S ultrasound unit. The analysis was performed with the Statistical Package for the Social Sciences (SPSS) version 20. Results: DVT was found in 36 (62.1%) patients with single closed fractures, 9 (15.5%) patients with single opened fractures, 10 (17.2%) patients with multiple closed fractures, and in 3 (5.2%) patients with multiple opened fractures. Sensitivity and specificity of the findings of compressibility and phasicity for DVT detection in patients with fractured lower extremities were 81.25% and 87.50% and 100% and 100% respectively. In addition, the absence of compressibility and phasicity had positive predictive value of 100% and 100% and negative predictive value of 93.75% and 95.65% respectively. Conclusions: US of DVs in the brightness mode (B-mode) with compression maneuvers should be the first-line imaging modality for suspected DVT in patients with fractured lower extremities

Duplex ultrasound for evaluation of deep venous blood flow in fractured lower extremities

Purpose: Early identification of deep venous thrombosis (DVT) in trauma patients would result in an early initiation of treatment, thereby decreasing the frequency of complications. The aim of the current study was to evaluate the role of duplex ultrasound (DUS) in the evaluation of deep venous blood flow in fractured lower extremities to rule out DVT prior to orthopedic surgery. Material and methods: In this prospective study a total of 58 patients (42 males and 16 females; mean age of 51.5 ± 19.5 years) with fractured lower extremities were thoroughly evaluated prior to surgery with respect to medical history, fracture pattern, associated injuries, comorbid conditions, and venous duplex ultrasound (VDUS) findings. Each affected limb was assessed for the presence of DVT using a Sonoline G 60S ultrasound unit. The analysis was performed with the Statistical Package for the Social Sciences (SPSS) version 20. Results: DVT was found in 36 (62.1%) patients with single closed fractures, 9 (15.5%) patients with single opened fractures, 10 (17.2%) patients with multiple closed fractures, and in 3 (5.2%) patients with multiple opened fractures. Sensitivity and specificity of the findings of compressibility and phasicity for DVT detection in patients with fractured lower extremities were 81.25% and 87.50% and 100% and 100% respectively. In addition, the absence of compressibility and phasicity had positive predictive value of 100% and 100% and negative predictive value of 93.75% and 95.65% respectively. Conclusions: US of DVs in the brightness mode (B-mode) with compression maneuvers should be the first-line imaging modality for suspected DVT in patients with fractured lower extremities

Perbandingan ciri anatomi daun Tetrastigma rafflesiae (Miq.) Planchon dan Tetrastigma pedunculare (Wall. ex Laws.) Planch. di Semenanjung Malaysia

Kajian ini bertujuan untuk melakukan kajian terhadap ciri anatomi daun Tetrastigma rafflesiae (Miq.) Planchon dan Tetrastigma pedunculare (Wall. ex Laws.) Planch. yang merupakan perumah kepada bunga pakma dan pakma tikus di Semenanjung Malaysia. Sampel daun diperoleh daripada habitat asal iaitu Gunung Bubu, Gerik, Perak. Teknik piawai dalam anatomi tumbuhan digunakan dan imbasan adalah menggunakan mikroskop cahaya dan mikroskrop imbasan elektron (SEM) dengan pemerhatian dilakukan meliputi bahagian petiol, tulang daun, lamina, epidermis dan peruratan daun. Hasil menunjukkan kehadiran trikom dan sel arenkima hanya terdapat pada T. pedunculare sahaja. Bilangan berkas vaskular medula pada T. rafflesiae adalah tunggal, manakala T. pedunculare adalah tiga. Oleh itu, ketiga-tiga ciri ini dapat membezakan dengan jelas kedua-dua spesies

Antioxidant Activity of Andrographolide from Andrographis paniculata leaf and Its Extraction Optimization by using Accelerated Solvent Extraction

Andrographis paniculata is widely used as a medicinal plant in many countries and andrographolide is the major bioactive compound extracted from A. paniculata leaf. This study purposely to optimize statistical andrographolide extraction using the accelerated solvent extraction (ASE) technique. The Box Behnken design (BBD) was chosen to determine the optimum ASE conditions for the extraction temperature (ºC), cycle number, and extraction time (min) to achieve the highest yield of andrographolide. The optimum ASE conditions were identified as: extraction temperature of 60 ºC, using 3 cycles and 5 min extraction time, with maximum conversion yield as high as 335.2 ± 0.2 mg/g determined by High Performance Liquid Chromatography (HPLC) with the squared correlation coefficients (R2) of 0.97. The findings revealed the ASE method significantly enhanced andrographolide extraction and agreed closely with the predicted value at 337.5 mg/g. Andrographolide was isolated by preparative HPLC technique. A. paniculata leaf extract and extracted andrographolide displayed moderate radical scavenging activity in 2, 2−Diphenyl−1−picrylhydrazyl hydrate (DPPH) assay with IC50 of 0.883 ± 1.597 mg/ml and 0.514 ± 0.285 mg/ml respectively as IC50 for ascorbic acid was 0.048 ± 0.004 mg/ml.  A. paniculata extract and andrographolide inhibited the tyrosinase enzyme with IC50 of 0.749 ± 0.293 μg/ml and IC50 of 2.441 ± 2.026 μg/ml indicated stronger tyrosinase inhibition abilities than kojic acid, IC50 of 19.985 ± 0.557 μg/ml. These results suggest that A. paniculata leaf extract and andrographolide have greater potential as sources of biochemical compounds that can be used as skin depigmentation solutions