Deterioration rate of renewable polyurethanes composites prior to ultra violet irradiation exposure

Polyurethanes (PU's) made from renewable and sustainable materials are one of the most important groups of polymers because of their versatility with wide range of grades, densities and stiffness. In this project, polymers based on renewable materials such as rapeseed (RS) and sunflower oil (SF) were synthesized and cross-linked to form polyurethanes. The effect of prolonged exposure up to 1000 h upon UVB light, in general promotes photodegradation for both RS and SF-based polyurethanes, both neat and also composites loaded with TiO2. The addition of 10% Degussa P25 TiO2 pigment, gives the greater degradation while PUs loaded with 5% Kronos 2220 show the slowest rates of degradation due to the effect of the coating of this pigment. The photostabiliser Tinuvin 770 offers high protection from UVB, thus lead the combination of Tinuvin 770 with Degussa P25 promotes the highest protection from UVB exposure. Moreover, addition of Tinuvin 770 at the stage of preparation of the PUs also greatly reduced the undesirable yellow colouration prevalent during PU synthesis

Segmented phase of ultraviolet (UV) curable thermoset polyurethanes-graphite (TPU-G) composites

Segmented thermoset polymeric materials properties mainly classified through its carbonyl hydrogen bonding. The addition of graphite particle loading in polymeric materials tailored the functional characteristic of the composites. Therefore, the carbonyl hydrogen bonding in the hard segments of the synthesized segmented ultraviolet (UV) curable thermoset polyurethanes-graphite (TPU-G) composites was identified. This composites based green polymer incorporated with varying graphite particles loading were prepared through slip casting method which cure upon UV light. These result in an enhancement of the carbonyl hydrogen bonding which tribute to degree of phase separation (DPS %) in the TPU-G composites ranged from 10-20%, as compared to that in the pure TPU. In addition, the spectroscopy detects the formation of carbonyl hydrogen groups within the TPU-G composites although they are prone to chain scission and undergo photo oxidation subjected to ultraviolet (UV) curing. Upon UV curing, higher graphite weight loading (TPU-G20, TPU-G25 and TPU-G30 composites), shows higher and stable DPS% value, attribute to soft segment- soft segment and hard segment- hard segment establishment. Therefore, the graphite particles dominantly absorb the incident radiation instead of thermoset polyurethane without changing its based

Identifying prognostic indicators for electrical treeing in solid insulation through pulse sequence analysis

Predictive maintenance attempts to evaluate the condition of equipment and predict the future trend of the equipment's aging, in order to reduce costs when compared to the two traditional approaches: corrective and preventive maintenance. This prediction requires an accurate prognostic model of aging. In solid insulation, the ultimate goal of prognostics is to predict the advent of failure, i.e., insulation breakdown, in terms of remaining useful life (RUL). One fault is electrical treeing, which is progressive thus leading to potentially catastrophic failure. Research has shown that diagnosis of faults can be achieved based on partial discharge (PD) monitoring [1], i.e., phase-resolved and pulse sequence analysis (PSA). This work will explore the extension of this concept towards predicting evolution of the defect: moving beyond diagnostics towards prognostics. To do this, there is a need for further investigation of prognostic features within PD characteristics leading up to breakdown. In this work, a needle-plane test arrangement was set up using a hypodermic needle and pre-formed silicone rubber as test samples. The visual observations and tree growth measurements were made using a digital microscope. PD data was captured using a radio frequency (RF) sensor and analysed using PSA. The main idea of the PSA approach is the strong relationship between two consecutive pulses caused by PD activities, which can give an understanding of the local degradation processes [1]. As for electrical treeing, a breakdown indicator in PSA is the appearance of heavily clustered data points that lie diagonally in scatter plots of the differential ratio of voltage and time of consecutive charges (Un = Δun/Δtn) [2,3]. Figure 1 shows an example of a plot that changed to a diagonal line after 14 hours of aging time. This paper investigates the formation of the diagonal line based on the distribution of the plot from the start of electrical treeing until breakdown occurs. Finally, statistical features of the PSA plot are given and will be used for lifetime prediction of insulation samples in future work

Malaysian and Indonesian Learners: They Are Judges of How They Learn English Most Effectively in and Out of Classrooms

The position of English is that of a Second Language in Malaysia and a Foreign Language in Indonesia. But the objective is the same that is to enable the learners to communicate effectively and efficiently in social and professional situations. Learners' beliefs and learners' strategies are also part of the learning processes. Strategies are ways of managing the complex information that the learners are receiving about the target language. This study aims to find out (i) the learners' beliefs on the importance of English (ii) what the learners will do (strategies) to manage their own learning. 100 respondents participated in the study. They responded to open ended questions. The results show that there are similarities and differences in the ways the Malaysian and Indonesian learners perceived the importance of English. They also have similarities and differences in their strategies to manage their own learning to achieve their goals. As a conclusion, even though the two countries adopted different language policy, the learners of English as a Second and Foreign Language have their own enthusiasms and they make judgements about how to learn the language effectively and they have the awareness of what language learning is like

Forecasting wind speed data by using a combination of ARIMA model with single exponential smoothing

Wind serves as natural resources as the solution to minimize global warming and has been commonly used to produce electricity. Because of their uncontrollable wind characteristics, wind speed forecasting is considered one of the best challenges in developing power generation. The Autoregressive Integrated Moving Average (ARIMA), Simple Exponential Smoothing (SES) and a hybrid model combination of ARIMA and SES will be used in this study to predict the wind speed. The mean absolute percentage error (MAPE) and the root mean square error (RMSE) are used as measurement of efficiency. The hybrid model provides a positive outcome for predicting wind speed compare to the single model of ARIMA and SES

A Narrative Analysis Using the Concept of Tabligh on the Obligation of Financial Statements Disclosure

Facts show that the rate of the disclosure financial statements by full-fledged sharia financecompaniesinIndonesiaisstillhighlylimited.Outofthreecompanies,onlyPT.Al Ijarah Indonesia Finance which give full and voluntary financial statements disclosure. This research aims to reveal the motivation of financial statements disclosure by full-fledged sharia finance companies using the concept of tabligh. This research uses theparadigmof tauhidandqualitativeapproach.Dataiscollectedbyintervieweingfour key informants from PT Al Ijarah Indonesia Finance to uncover motives and document study. Data is analyzed using Greimas’ structural narrative analysis and combined with the concept of tabligh. The results of the research show that the motive of financial statements disclosure by PT Al Ijarah Indonesia Finance is to communicate (tabligh) the financial statements to the stakeholders so that a broad and clear picture of the company is provided. Communicating (tabligh) informations broadly and clearly is what PT Al Ijarah Indonesia Finance aims for, which can be explained in several narrative relations; first, internal relations in which the constraints of ALIF internal disclosure become the consideration for the publication goodwill, which when combined with the concept of tabligh becomes the foundation of the disclosure. Second, the extent and content of the disclosure in the relation of subject and object as an informative disclosure, and when combined with the concept of tabligh becomes an extensive disclosure. The last relation is the disclosure media as the target of disclosure in the relation of sender and receiver, so that when combined with the concept of tabligh it becomes an effective act of communication