Image reconstruction using iterative transpose algorithm for optical tomography

This paper describes a transpose algorithm for use with an optical tomography system. The measurement system consisted of two orthogonal arrays, each having ten parallel views, resulting in a total of twenty sensors. The measurement section is divided into hundred equi-sized pixels. The forward problem is modelled by allocating an optical attenuation coefficient to each pixel. The attenuation of incident collimated light beams is then modelled using the Lambert-Beer law. The inverse problem is defined and the transpose of the sensitivity matrix is used to obtain an estimate of the attenuation coefficients in each pixel. The iterative method is investigated as a means of improving reconstructed image qualit

Fabrication and characterization of modified ZnO-kapok fiber for separating surfactant-free oil-in-water emulsions

. Natural sorbents have several benefits, including high sorption capacity, superior biodegradability, and low cost. Kapok is one of the natural fibers that can be used as absorbent material. These distinctive qualities give kapok fibers greater oil sorption capacity than other oil sorbents currently on the market. However, it is difficult to hold oil properly due to its waxy coating and smooth fiber surface. Thus, in this study, the rough surface fiber has been coated using ZnO via the hydrothermal method. Considering that ZnO is instinctually hydrophilic, this modification of the fiber compounds increases the adsorption of oil in fiber. The surface morphology interaction has been proven with an experiment using a scanning electron microscope (SEM) for morphology investigation, Fourier-transform infrared spectroscopy (FTIR) for identifying organic or inorganic materials, and physical interaction (contact angle analysis). The results obtained display a significant difference between modified kapok fiber with ZnO and raw kapok fiber. The FTIR analysis shows that the modified kapok exhibits the peak's level of intensity at 3268.88 cm-1 (stretching vibration peak of surface –OH decreases obviously as compared with that of raw kapok fiber, an absorption peak (symmetric stretching vibration of Zn–O–Zn) is observed at 652.28 cm-1. These results suggested that the whole sum of –OH was diminished, and hydrophobic ZnO nanoparticles were developed on the kapok fiber's surface. A surface morphology analysis using SEM shows that ZnO particles are present on the kapok fiber surface while comparing it to the raw kapok. Modified kapok shows a higher contact angle (138°) compared to raw kapok (125.5°). This can conclude that the kapok fiber modification was successfully achieved using the hydrothermal metho

Fabrication and characterization of modified ZnO- kapok fiber for separating surfactant-free oil-in-water emulsions

Natural sorbents have several benefits, including high sorption capacity, superior biodegradability, and low cost. Kapok is one of the natural fibers that can be used as absorbent material. These distinctive qualities give kapok fibers greater oil sorption capacity than other oil sorbents currently on the market. However, it is difficult to hold oil properly due to its waxy coating and smooth fiber surface. Thus, in this study, the rough surface fiber has been coated using ZnO via the hydrothermal method. Considering that ZnO is instinctually hydrophilic, this modification of the fiber compounds increases the adsorption of oil in fiber. The surface morphology interaction has been proven with an experiment using a scanning electron microscope (SEM) for morphology investigation, Fourier-transform infrared spectroscopy (FTIR) for identifying organic or inorganic materials, and physical interaction (contact angle analysis). The results obtained display a significant difference between modified kapok fiber with ZnO and raw kapok fiber. The FTIR analysis shows that the modified kapok exhibits the peak's level of intensity at 3268.88 cm-1 (stretching vibration peak of surface –OH decreases obviously as compared with that of raw kapok fiber, an absorption peak (symmetric stretching vibration of Zn–O–Zn) is observed at 652.28 cm-1. These results suggested that the whole sum of –OH was diminished, and hydrophobic ZnO nanoparticles were developed on the kapok fiber's surface. A surface morphology analysis using SEM shows that ZnO particles are present on the kapok fiber surface while comparing it to the raw kapok. Modified kapok shows a higher contact angle (138°) compared to raw kapok (125.5°). This can conclude that the kapok fiber modification was successfully achieved using the hydrothermal metho

Characterization of a Magnetorheological Fluid Damper Applied to Semi-Active Engine Mounting System / M. Hafiz Harun...[et al.]

This study is to propose a hysteresis damper model that can be integrated with the vehicle control system. A prototype of magnetorheological for engine mounting has been designed and tested to realize the objective of this study. The experimental on the prototype of the magnetorheological damper for engine mounts has been conducted in order to investigate the hysteresis of this damper. From the experiment, the results are evaluated in terms of damping force versus piston displacement and also the damping force versus piston velocity. It is significantly shows that the proposed model satisfy the non-linear hysteresis behavior of the MR damper in the form of force-velocity and force-displacement characteristics

The oil sorption behaviour investigation of kapok (Ceiba Pentandra (L.)) fiber

As oil exploration and production activities have risen globally, water contamination from oil spills and the discharge of other oily wastewaters has emerged as one of the primary environmental concerns. Thus, Kapok fiber is considered in this study as it is known as one of the most effective method for cleaning up and collecting oil spills where Kapok is a natural cellulosic fiber with unique characteristics. A critical investigation was conducted to study the potential of kapok fiber as sorbent material, also analyze the surface properties of kapok fiber for the ability of kapok fiber to absorb oil and investigate the sorption mechanisms of kapok fiber. Therefore, the surface properties of kapok fiber were analyzed using SEM, FTIR, TGA and contact angle. To investigate the selectivity nature and the sorption capacity of 5 g kapok fiber, different types of oil and different apparent viscosity were used. The types of oil used are gear oil (low viscosity), vegetable oil-based cooking oil (medium viscosity) and waste oil (high viscosity). Kapok fiber was able to absorb all types of oil, with wasted oil absorbing the most about 17.88 g.g-1. Scanning electron microscopy (SEM) was used to examine the morphology of raw kapok fiber. In this study, kapok fiber was shown to have a porous hollow lumen structure and a waxy coating on the surface. Other than that, for the contact angle analysis, kapok fiber had high water contact angle up to 130˚. The water droplet was stood on the kapok fibers surfaces before and after absorption with contact angles ranging from 130˚ to 145˚. In contrast, the oil droplet had disappeared from the surfaces of kapok fiber within a few second

Online performance dialogue system model (e-DP): a requirement analysis study at Batu Pahat district education office

This study aims to identify the viewpoint of school leaders the need of developing Online Performance Dialogue (EDP). The model based on the method of inquiry for educational leaders and the School District. The theory is used as a model UTAUT basis for this study. Survey methods used between 222 schools investigate the needs of leaders to adopt Online Performance Dialog (eDP) The data obtained were analyzed through descriptive Statistics using statistical package for social science (SPSS) software. Interpretation of the data is based on the value of the mean and standard deviation. Overall findings indicate that school leaders need on-line performance dialogue (eDP) with an average mean 4.309. The findings of this study reveal that school leaders have access to the necessary technology to eDP. The results also showed the level of acceptance and the intention to use the eDP model among school leaders

Drag-Reduction Study and its Dynamic Characteristics on Recreational Speedboat Utilizing Simplified Shark Skin Design

Inspired by the structure of the shark skin denticles, our team has carried out a study on the attempt of improving the hydrodynamic design of marine vessels through design modification on the hull form by applying simplified imitation of shark skins. Speedboat models used in this study were designed using computer-aided design (CAD) software and computational fluid dynamic (CFD) simulations were then carried out to predict the hydrodynamic effect of the bio mimicry application on the hull form, mainly focusing on the wave profile produced by the models as well as the total drag experienced by it under two different Froude value; Fr≈ 0.39 and Fr≈0.47. Interestingly, the design modification on the hull gave encouraging results with a reduction of 12% and 10.4% at Fr≈ 0.39 and Fr≈0.47 respectively on the total drag coefficient. Furthermore, the modified speedboat provides better wave pattern compared to unmodified hull form. The reduction of drag force could contribute to a more efficient vessel with better cruising speed. Thus, this provide better impact to marine industry in order to help improve their vessel dynamic performances

Development of an indoor air quality checklist for risk assessment of indoor air pollutants by semiquantitative score in nonindustrial workplaces

Background: To meet the current diversified health needs in workplaces, especially in nonindustrial workplaces in developing countries, an indoor air quality (IAQ) component of a participatory occupational safety and health survey should be included. Objectives: The purpose of this study was to evaluate and suggest a multidisciplinary, integrated IAQ checklist for evaluating the health risk of building occupants. This IAQ checklist proposed to support employers, workers, and assessors in understanding a wide range of important elements in the indoor air environment to promote awareness in nonindustrial workplaces. Methods: The general structure of and specific items in the IAQ checklist were discussed in a focus group meeting with IAQ assessors based upon the result of a literature review, previous industrial code of practice, and previous interviews with company employers and workers. Results: For practicality and validity, several sessions were held to elicit the opinions of company members, and, as a result, modifications were made. The newly developed IAQ checklist was finally formulated, consisting of seven core areas, nine technical areas, and 71 essential items. Each item was linked to a suitable section in the Industry Code of Practice on Indoor Air Quality published by the Department of Occupational Safety and Health. Conclusion: Combined usage of an IAQ checklist with the information from the Industry Code of Practice on Indoor Air Quality would provide easily comprehensible information and practical support. Intervention and evaluation studies using this newly developed IAQ checklist will clarify the effectiveness of a new approach in evaluating the risk of indoor air pollutants in the workplace

Impact of chloride and strong ion difference on ICU and hospital mortality in a mixed intensive care population

BACKGROUND: Abnormal chloride levels are commonly observed in critically ill patients, but their clinical relevance remains a matter of debate. We examined the association between abnormal chloremia and ICU and hospital mortality. To further refine findings and integrate them into the ongoing discussion on the detrimental effects of chloride-rich solutions, the impact of strong ion difference (SID) on the same end points was assessed. METHODS: Retrospective cohort study in an academic tertiary intensive care unit on 8830 adult patients who stayed at least 24 h in the ICU was carried out. Patients admitted after elective cardiac surgery were treated as a separate subgroup (n = 2350). Analyses were performed using multivariable logistic regression. All statistical models were extensively adjusted for confounders, including comorbidity, admission diagnosis, other electrolytes and acid–base parameters. RESULTS: Severe hyperchloremia (>110 mmol/L), but not low (SID) was significantly associated with increased mortality in the ICU (odds ratio vs. normochloremia 1.81; 95 % CI 1.32–2.50; p < 0.001) and the hospital (odds ratio 1.49; 95 % CI 1.14–1.96; p = 0.003). Hyperchloremia and low (SID) were encountered in the majority of patients admitted after cardiac surgery (in 86.9 and 47.2 %, respectively), but were not negatively associated with mortality. CONCLUSIONS: In the ICU, hyperchloremia at admission was associated with negative outcome. On the other hand, decreased strong ion difference did not have an impact on mortality, precluding a simple extrapolation of these findings to the ongoing discussion on the detrimental effects of chloride-rich solutions. This notion is fueled by the finding that hyperchloremia after cardiac surgery, frequently encountered and probably fluid-induced, did not seem to be deleterious. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13613-016-0193-x) contains supplementary material, which is available to authorized users