Phenomenology of The Left-Right Twin Higgs Model

The twin Higgs mechanism has recently been proposed to solve the little hierarchy problem. We study the implementation of the twin Higgs mechanism in left-right models. At TeV scale, heavy quark and gauge bosons appear, with rich collider phenomenology. In addition, there are extra Higgses, some of which couple to both the Standard Model fermion sector and the gauge sector, while others couple to the gauge bosons only. We present the particle spectrum, and study the general features of the collider phenomenology of this class of model at the Large Hadron Collider.Comment: 41 pages, version appears in PR

The learning environment in Singapore primary science classrooms : the ideal and the real

Data collected from 485 students from four coeducational primary schools in Singapore were used to: validate a modified learning environment and attitude questionnaire; investigate differences between students’ perceptions of their actual and preferred classroom learning environments; examine sex differences in learning environment perceptions and attitudes to science; and investigate associations between students’ attitudes and the nature of the classroom learning environment

A comparison of the antioxidant properties and total phenolic content in a Diatom, Chaetoceros sp. and a green microalga, Nannochloropsis sp.

The aquaculture industry commonly makes use of microalgae as live feed. Chaetoceros sp., a diatom, and Nannochloropsis sp., a unicellular green microalga, have both been reported to contain a substantial amount of polyunsaturated fatty acids and carotenoids. Their potential as natural sources of antioxidants has gained recent attention. This study focuses on determining the antioxidant properties of the different solvent extracts, namely hexane, dichloromethane, chloroform and methanol, from both microalgae. The evaluation of antioxidant capacities was done by Folin-ciocalteu, 1,1-diphenyl-2-picrylhydrazyl radical-scavenging, metal chelating, nitro-blue tetrazolium reduction and ferric-reducing antioxidant power assay. Results showed that the non-polar solvent extracts from the diatom were highest in antioxidant power, whereas both polar and non-polar solvent extracts of green microalgae showed good antioxidant potential. In general, Chaetoceros sp. had higher antioxidant capacities than Nannochloropsis sp. This study suggests that different solvent extracts contain different potential antioxidant compounds able to scavenge different types of free radicals

Nutritional compositions and antioxidant activities of non-polar and polar extracts of germinated brown rice

The objective of this study was to investigate the nutritional compositions and antioxidant activities (AA) of non-polar and polar extracts of germinated brown rice (GBR). Nutritional compositions such as moisture, ash, carbohydrate, fat, protein and fibre were determined. Energy and minerals content were determined by using bomb calorimetry and Atomic Absorption Spectroscopy (AAS), respectively. Total phenolic content (TPC) and total flavonoid content (TFC) of the extracts were determined by Folin-Ciocalteu method and aluminium chloride colorimetric method. The AA was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and [2,2′-Azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] diammonium salt (ABTS) radical scavenging capacity assay, ferric reducing antioxidant potential (FRAP) assay, and β-carotene bleaching assay. Total energy content of GBR sample was 390.95±11.31 kcal/100g and carbohydrate (54.30±1.04 g/100 g) was the most abundant nutrient. The predominant minerals in the GBR sample were sodium, potassium and magnesium. The polar extract showed significantly higher (p0.90, p<0.001) existed between antioxidants (TPC and TFC) and AA. Therefore, polar extract was better than non-polar extract. The nutritional composition of GBR also provided an update for food composition database

Enhanced device-based 3D object manipulation technique for handheld mobile augmented reality

3D object manipulation is one of the most important tasks for handheld mobile Augmented Reality (AR) towards its practical potential, especially for realworld assembly support. In this context, techniques used to manipulate 3D object is an important research area. Therefore, this study developed an improved device based interaction technique within handheld mobile AR interfaces to solve the large range 3D object rotation problem as well as issues related to 3D object position and orientation deviations in manipulating 3D object. The research firstly enhanced the existing device-based 3D object rotation technique with an innovative control structure that utilizes the handheld mobile device tilting and skewing amplitudes to determine the rotation axes and directions of the 3D object. Whenever the device is tilted or skewed exceeding the threshold values of the amplitudes, the 3D object rotation will start continuously with a pre-defined angular speed per second to prevent over-rotation of the handheld mobile device. This over-rotation is a common occurrence when using the existing technique to perform large-range 3D object rotations. The problem of over-rotation of the handheld mobile device needs to be solved since it causes a 3D object registration error and a 3D object display issue where the 3D object does not appear consistent within the user’s range of view. Secondly, restructuring the existing device-based 3D object manipulation technique was done by separating the degrees of freedom (DOF) of the 3D object translation and rotation to prevent the 3D object position and orientation deviations caused by the DOF integration that utilizes the same control structure for both tasks. Next, an improved device-based interaction technique, with better performance on task completion time for 3D object rotation unilaterally and 3D object manipulation comprehensively within handheld mobile AR interfaces was developed. A pilot test was carried out before other main tests to determine several pre-defined values designed in the control structure of the proposed 3D object rotation technique. A series of 3D object rotation and manipulation tasks was designed and developed as separate experimental tasks to benchmark both the proposed 3D object rotation and manipulation techniques with existing ones on task completion time (s). Two different groups of participants aged 19-24 years old were selected for both experiments, with each group consisting sixteen participants. Each participant had to complete twelve trials, which came to a total 192 trials per experiment for all the participants. Repeated measure analysis was used to analyze the data. The results obtained have statistically proven that the developed 3D object rotation technique markedly outpaced existing technique with significant shorter task completion times of 2.04s shorter on easy tasks and 3.09s shorter on hard tasks after comparing the mean times upon all successful trials. On the other hand, for the failed trials, the 3D object rotation technique was 4.99% more accurate on easy tasks and 1.78% more accurate on hard tasks in comparison to the existing technique. Similar results were also extended to 3D object manipulation tasks with an overall 9.529s significant shorter task completion time of the proposed manipulation technique as compared to the existing technique. Based on the findings, an improved device-based interaction technique has been successfully developed to address the insufficient functionalities of the current technique

The Influence of Accelerating Entropy Inhomogeneities on Combustor Thermoacoustics

The growing global concern over environmental emissions such as nitrogen oxides and noise sets challenging problems for aero-propulsion engineers. Acoustic waves generated by unsteady combustion not only contribute towards the overall noise transmission, but may also cause thermoacoustic instability in combustors, particularly those designed for low NOx emissions. Combustion noise is generated by unsteady combustion – either by the direct generation of acoustic waves or indirectly by the creation of entropy waves. Entropy waves by themselves are silent, but when accelerated, such as through the combustor exit, they create further acoustic waves known as entropy noise. This thesis aims to study transmitted and reflected combustion noise. Current predictions for noise transmission often assume that the wavelengths of the flow perturbations are large compared to the combustor length, known as the compact assumption. We will develop predictions for finite-length combustors accurate to first-order in frequency. The effect of the interaction between an oscillating shock wave with combustion noise is also studied analytically. The predictions agree with data from numerical simulations. Combustion acoustics reflected at the combustor exit may go on to interfere with the combustion process, setting up a feedback mechanism that may lead to thermoacoustic instability. A modified combustor model is presented to study the effect of dissipation and dispersion of entropy waves on the instability, and it was found that the extent of dissipation or dispersion not only plays a significant role on whether instability occurs, but also determines the dominant frequency of oscillations. Furthermore, analytical and numerical investigations suggest that entropy waves are convected with the flow undissipated, and that modelling improvements may be made to take entropy dispersion into account. The findings in this work provide better tools to understand indirect combustion acoustics and to analyse their importance in both transmitted combustion noise and the thermoacoustic instability experienced by low NOx combustors

Economic Evaluation And Factors Affecting Smoking Cessation Using Istop Program In A Local Manufacturing Company

Tobacco products are a double-edged sword. While tobacco products contribute to a country’s economic significantly, it is also a notable risk factor for human health and a silent thief of the wealth of its users, society and nation. Apart from the healthcare cost, the work performance of smokers is also being affected leading to lower productivity. Many studies have also shown that workplace smoking cessation programs are effective and have generated positive savings for the employers. Therefore, workplace smoking cessation has been viewed as a potential strategy to combat the usage of tobacco products. Abundant studies have been carried out abroad, but local studies are scares; especially in the private manufacturing sector. This study was a cross-sectional single prospective cohort workplace smoking cessation study conducted in a local manufacturing company. This study reviewed a 12-week innovative multi-component smoking cessation intervention program to support smoking employees to quit smoking, called “iSTOP” program. The objectives of this study were to evaluate the effectiveness of this innovative program and the smokers’ behaviours as well as to identify factors affecting smoking cessation and relapse. On top of these, the quality of this program was also evaluated using qualitative analysis method, making it more effective in assisting smokers to quit smoking. As this was the Company fully sponsored program, the last section was to calculate the economic return this program to the employer using the common commercial indicators (ROI and IRR), which are familiar by the Management team