11,445 research outputs found

    The effects of continuous lighting (CL) method on the growth development of brassica chinensis for led plant factory in wsn application

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    This study was performed to investigate the best practise on using LED light for optimum growth of Brassica Chinensis and reduce turn around time at different kind of photoperiod study utilizing Wireless Sensor Network (WSN) technology as remote monitoring system. Growth performance of Brassica Chinensis under two different wavelengths (blue and red) 16: 4 as light source has been used to determine plant growth performance and phytochemicals aspect of plant characteristics. Two experiments were conducted which is the pulse treatment (1 hour light and 1 hour dark) and continuous light (CL) photoperiod treatment in both trials. Observation such as leaves count, height, dry weight and chlorophy I & ll of both plants were analysed. It was noted that the CL photoperiod has significant effect on overall growth performance and remarkably lead to improve the efficiency of the plant factory. In order to reason on data and monitor the environmental parameters of the plant factory, an intelligent system using embedded system has been developed to automate the LED control and manipulation. The result shows that the system is stable and has referential significantly in the area of plant factory or indoor farming system

    The Onset of Chaos in Pulsating Variable Stars

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    Random changes in pulsation period occur in cool pulsating Mira variables, Type A, B, and C semiregular variables, RV Tauri variables, and in most classical Cepheids. The physical processes responsible for such fluctuations are uncertain, but presumably originate in temporal modifications of the envelope convection in such stars. Such fluctuations are seemingly random over a few pulsation cycles of the stars, but are dominated by the regularity of the primary pulsation over the long term. The magnitude of stochasticity in pulsating stars appears to be linked directly to their dimensions, although not in simple fashion. It is relatively larger in M supergiants, for example, than in short-period Cepheids, but is common enough that it can be detected in visual observations for many types of pulsating stars. Although chaos was discovered in such stars 80 years ago, detection of its general presence in the group has only been possible in recent studies.Comment: To appear in the proceedings of the Odessa Variable Stars 2010 Conference (see http://uavso.org.ua/?page=vs2010&lang=en), edited by I. Andronov and V. Kovtyuk

    Linear-nonlinear stiffness responses of carbon fiber-reinforced polymer composite materials and structures: a numerical study

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    The stiffness response or load-deformation/displacement behavior is the most important mechanical behavior that frequently being utilized for validation of the mathematical-physical models representing the mechanical behavior of solid objects in numerical method, compared to actual experimental data. This numerical study aims to investigate the linear-nonlinear stiffness behavior of carbon fiber-reinforced polymer (CFRP) composites at material and structural levels, and its dependency to the sets of individual/group elastic and damage model parameters. In this regard, a validated constitutive damage model, elastic-damage properties as reference data, and simulation process, that account for elastic, yielding, and damage evolution, are considered in the finite element model development process. The linear-nonlinear stiffness responses of four cases are examined, including a unidirectional CFRP composite laminate (material level) under tensile load, and also three multidirectional composite structures under flexural loads. The result indicated a direct dependency of the stiffness response at the material level to the elastic properties. However, the stiffness behavior of the composite structures depends both on the structural configuration, geometry, lay-ups as well as the mechanical properties of the CFRP composite. The value of maximum reaction force and displacement of the composite structures, as well as the nonlinear response of the structures are highly dependent not only to the mechanical properties, but also to the geometry and the configuration of the structures

    E-Learning acceptance in a developing country: A case of the Indonesian Open University

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    The rapid proliferation of the number people using the Internet and World Wide Web (WWW) has been identified by many academic institutions as a potential opportunity to promote distance learning activity. E-learning has been implemented by academic institutions worldwide for decades, including the Indonesian Open University. In this study, using the Indonesian Open University or Universitas Terbuka (UT) as study setting, we investigate the factors that were believed to affect acceptance of e-learning namely, computer self-efficacy, convenience, instructor’s characteristics, instructional design, technological factors and institutional support. All these factors were examined to predict their contribution to the Technology Acceptance Model (TAM). From the literature, we developed a research model and eleven hypotheses. The research model was tested using structural equation modeling technique. The research findings suggest several implications and contributions to the e-learning knowledge and concept. The results provide interesting insights and suggestions. Instructional design (ID) and technological factors (TF) were shown to be strong predictors of both perceived ease of use (PEOU) and perceived usefulness (PU). Consistent with prior studies, CSE was confirmed to predict perceived usefulness. Other variables; convenience (CONV) and instructor’s characteristics (IC) are found to be non-significant factors for perceived ease of use (PEOU). Perceived ease of use was found to be a strong predictor of perceived usefulness and intention to use

    The Development Of High Temperature Recirculating Pump (HTRP) For Energy Savings In An Incinerator.

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    Tremendous increase ingeneration of Municipal Solid Waste (MSW) has become a major concern for the Malaysian government as the country experiencing rapid development. It was estimated about 16000 tones/day MSW is produced at national level and in Kuala Lumpur alone about 2500 tones/day

    A new degree six modified chordal ring network topology

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    The performance of a parallel or distributed network depends on the design of its interconnection topology. One good network interconnection topology that has been the focus of various researchers is the chordal ring. In this paper, a new degree six modified chordal ring is presented, the optimised degree six 3-modified chordal ring (CHR6o3), with the aim of comparing its performance parameters in terms of optimal diameter and optimal average path length to existing degree six chordal rings. Formulae to generate the data for each different chordal ring were derived from its corresponding tree visualisation or used from previous work. Network sizes tested were from 1200 to 12000 nodes. Large networks of CHR6o3 were shown to perform better than those of previous degree six chordal rings. This gives CHR6o3 an added advantage for its implementation in large distributive networks, such as Fibre to the Home (FTTH) networks, since it offers redundancies at higher network layers

    Locus of control, attributions and impression management in the selection interview

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    Surprisingly little is known about the ways in which candidates create positive impressions during employment interviews. Three studies are presented which investigate how candidate and interviewer locus of control influence preferences for three categories of explanations proffered by candidates during graduate recruitment interviews. In Study 1, we asked 139 undergraduate students and 37 personnel managers to rate internal-controllable, internal-uncontrollable and externaluncontrollable candidate attributions for hypothetical past events according to the likelihood of each producing a positive impression during a selection interview. Students also completed Rotter's Locus of Control questionnaire and the Interview Behaviour Scales. Students and personnel managers rated internal-controllable attributions most likely to create a positive impression. However, students with an external LoC rated external-uncontrollable explanations and internal-controllable explanations as being equally likely to convey a positive impression. In Study 2 a group of 62 candidates applying for actual positions with a company completed the same attribution questionnaire prior to first-stage interviews. Interviewer ratings of candidate performance correlated positively with ratings of internal-controllable explanations (r =.36, p< .001). In Study 3, a sample of 103 experienced interviewers completed the attribution questionnaire and the WLOC. All interviewers rated internal-controllable attributions most likely to convey a positive impression of a candidate. However, locus of control mediated preference for candidate attributions such that ‘External’ interviewers rated external-uncontrollable attributions significantly more likely to convey a positive impression than ‘Internal’ interviewers. The implications of these findings for impression management and interview selection decisions are discussed

    Radiation grafted natural fibres functionalized with alkalised amine for transesterification of cottonseed oil to biodiesel

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    Poly(glycidyl methacrylate) grafted Linum usitatissimum (flax) fibers functionalized with diethylamine (DEA) groups followed by alkalisation were prepared and used as a heterogeneous catalyst for production of biodiesel. Particularly, the new basic catalyst was used for transesterification of cottonseed oil using different molar ratios with methanol and various reaction temperatures. The gas chromatography analysis was used to confirm the conversion of the cottonseed oil to biodiesel. The transesterification reaction temperature affected the conversion percentage significantly. The highest conversion was obtained at 60 °C. In addition, the oil/methanol ratio in the reaction mixture of 1:33 resulted in the highest conversion ratio reaching about 97 %. These results suggest that the alkaline organic catalyst prepared in this study has a potential for application in biodiesel production
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