635 research outputs found
Modeling and Trajectory Tracking Control of Robot Manipulators for Laser Cutting Industrial Application.
Robot manipulators are electromechanical devices whose functionality is similar to that of the arms of human beings. The problem with robot manipulators is that they are open loop unstable systems so it is important to stabilize the response of the robot manipulator. In this research project the robot manipulator is used for an industrial application of Laser Cutting. For this purpose trajectory tracking is important. The user will define any desired trajectory and the robot manipulator’s end effector is supposed to track the desired generated trajectory. For this purpose a PID controller is used which is tuned using iterative method. In this research work, simulations are carried out on a 2R robot manipulator with end griper using Simulink / Matlab Software. The end gripper is supposed to hold the laser that is meant to cut an object in a shape defined by user. In this paper, kinematic & dynamic models of robot manipulator, with and without uncertainties, will be presented and a PID controller will be designed to track the desired trajectory of the end effectorfor laser cutting applications Keywords:Robot manipulator, Kinematics, trajectory tracking, PID controller, Joint Space, Joint variables, Work Space, End effector
The Influence of Information Technology on Student’s Behavioural Nature in the Class Room
The use of mobile phones and other gadgets in the university class room is becoming a culture in the modern age of technology. Some students use this technology for the purpose of information only. However, it was noted that others use mobile phone to receive messages through different applications such as WhatsApp, Facebook, Instagram and Viber. It is therefore important to understand the impacts of their behaviour. On the other hand, the use of mobile technology effects the teaching strategies. Teachers need to adopt new teaching methodologies to make sure that educational objectives and student’s deep learning could be achieved together. It is therefore critical to adopt a balance approach. The research in this paper conducted a survey to find the relationship between student’s behaviour and the use of mobile technology. The analysed data is used to balance the approach and to achieve educational objectives
Pre-harvest factors affecting quality and shelf-life in raspberries and blackberries (Rubus spp. L.)
Fruit including berries have been demonstrated to exhibit a broad spectrum of benefits including protection against cardiovascular, neurological, and lung diseases, as well as having antioxidant, antimicrobial, anti-inflammatory, anti- diabetic and anti-aging properties. These protective effects are reported to be due to their high content of bioactive compounds, such as vitamin C, vitamin E, phenolic acids, ellagitannins, flavonoids and carotenoids. This thesis investigated the effect of pre- and postharvest factors on the concentrations of bioactive compounds in raspberries and blackberries. The factors studied included genetic variability, organic and synthetic fertilizers, seasonal variation (harvest-to-harvest and annual variation) in greenhouse, high tunnel and open field production, and post-harvest storage. Concentrations of bioactive compounds (anthocyanins, vitamin C, ellagic acid, carotenoids) in the berries, or in the leaves, were quantitatively analysed by high-performance liquid chromatography, and total phenolics were analysed by a spectrophotometric method. Generative parameters (yield, fruit size) investigated for the cultivar difference and organic nitrogen, responded differently to the nitrogen level within cultivars and varied significantly in primocane raspberries. Taste compounds, such as total acidity and different sugars, varied during the season and with nutrient regimes. Time of harvest also affected the ellagic acid content, which was high in early season, and the vitamin C content, which was high in late season in primocane raspberries. Significant changes were also found between different years. Vitamin C decreased significantly with high synthetic N and with low K application, but the application of high N with high K showed positive influence in the level of nutrients and bioactive compounds in blackberries except for ellagic acid. Increased level of organic fertilization (12-17 g N/plant) in primocane raspberries caused only minor changes in the analysed compounds. The post-harvest performance of raspberries regarding the levels of bioactive compounds was less dynamic than in blackberries. In addition, raspberries harvested in late season showed comparatively less changes in sugar content during storage as compared to early harvest, indicating less enzymatic activity in the late season
The Design of Curriculum, Assessment and Evaluation in Higher Education with Constructive Alignment
In higher education, the principle of constructive alignment for devising teaching, learning activities and assessment tasks is the underpinning concept in curriculum design and development to achieve intended learning outcomes. Student’s deep learning is critical and it is the responsibility of the curriculum developer to make sure that synergy between formative and summative assessment is achieved. Also, the needs for special education must be addressed and diversity must be achieved through multiple channels throughout the process of learning, teaching and assessment. Constructive alignment is considered as a key element in education design. However, this requires time and effort in designing teaching and assessment. Due to the importance of constructive alignment, the research in this paper discusses issues relevant to the process of curriculum design and development with the emphasis on students with special needs. Conclusion is drawn based on the literature review
The Determinants of Leverage of the Listed-Textile Companies in India
This study examines the determinants of leverage of Indian textile firms using panel data analysis. The sample of the study covers 170 Indian textile companies listed on the Bombay Stock Exchange covering the period from 2006 to 2010. Fixed effects regression model was used for the analysis of penal data of sample companies. Firm size, growth in total assets, non-debt tax shields, profitability and asset tangibility are used as explanatory variables, while leverage ratio is the dependent variable in the model. The results show that the variables of size, non-debt tax shields, and tangibility have highly significant positive relationship with the leverage ratio (p<0.01), while on the contrary, growth and profitability have highly significant negative relationship with debt ratio (p<0.01). The results are generally consistent with theoretical predictions as well as previous research papers. This paper adds to the existing literature on the relationship between the firm specific factors and leverage Keywords: leverage, capital structure, firm-specific factors, textile industry, penal dat
Towards organisational cultural alignment of strategic information systems planning (SISP) methodologies.
Available from British Library Document Supply Centre-DSC:DX210010 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
Use of Case Histories to Enhance Practical Geotechnical Engineering
A geotechnical case history is a complete cycle; spread over events such as, investigation, design, execution, completion, and monitoring, of understudy project. In case histories the events are continuously monitored, evaluated, modified (if required), executed and corresponding responses / effects are recorded. Case histories help us learn from the past without living in the past, their analysis envision us to enhance practical engineering in the present and future. A geotechnical case history may be performed in an organizational framework or initiated by an interested research engineer in an individual capacity. In all circumstances; a case history would aim at exploring questions concerning processes or techniques for a future project or testing of hypotheses based on the existing theoretical concepts. A case history therefore is an important research tool for educational evaluation and practical geotechnical engineering. Availability of up-to-date data sets of geotechnical case histories covering entire spectrum; from techniques / technologies to results / effects can help reduce both cost and time of future geotechnical projects. Knowledge gained from case histories can be used to develop geotechnical analytical models for optimization of designs. This paper is a case history of “Enhancement of Bearing Capacity by Dynamic Compaction” project carried out in alluvial deposits, in Pakistan. The authors intend analyzing the project with a view to contribute towards increased understanding of improvement of alluvial deposits by dynamic compaction technique
From Case Histories to Conceptual Models
Geotechnical engineering deals with complicated and highly variable set of engineering principles. A typical geotechnical engineering project comprises site characterization, foundation / soil treatment design, execution, monitoring and quality control systems. Unlike some other civil engineering designs, highly variable soil conditions make a geotechnical designs an iterative and repetitive process which in-turn make these designs cost and time intensive. Economy and optimization of geotechnical designs are dependent on comprehensive site characterization and evaluation of multiple alternatives. Availability of up-to-date data sets of geotechnical case histories covering entire spectrum; from techniques / technologies to results can help reduce both cost and time of future geotechnical projects. Knowledge from case histories can be used to develop geotechnical constitutive and analytical models with the help of information technology; such models can lead us to many progressive and futuristic limits of geotechnical engineering. The authors of the paper intend to propose architectural development of “Geotechnical Information System (GTIS)”. The GTIS system covering fundamental geotechnical concepts, data of case histories such as; techniques, technologies employed, monitoring and quality control systems, results / effectiveness of techniques, will provide a framework for the following: • increased understanding of world-wide geotechnical issues by sharing lessons learnt which will help minimize barriers of uncertainty • enhancement of investigation and design procedures • development of economical and efficient technologies • identification of areas for collaborative research • development of “Geotechnical Artificial Intelligence Systems (GTAIS)
Enhancement of Bearing Capacity by Dynamic Compaction: A Case History
Deep Dynamic Compaction technique was used to improve soil bearing capacity in one of the project in Pakistan. It was first project in the country where Deep Dynamic Compaction technique was used for soil improvement. The soil at construction site composed of alluvial deposits. The sub-surface profile with in the depth of influence of proposed structure comprised of different layers of varying thickness within the construction site. The top 1-2 meter strata was an imported fill compacted in layers and composed of sandy silty clayey soil with percentage of fines as high as 75 percent The water table was located at 12 m depth. The construction alternatives included deep foundation and improvement of bearing capacity using dynamic compaction technique; the later was adopted in view of the economy of the project. The depth and degree of improvement was evaluated by comparing pre to post compaction Standard Penetration Tests (SPT) and measuring depth of the crater after each drop. The paper discusses briefly the compaction design, methodology for evaluation of effectiveness and resultant improvement in depth and lateral direction. The results of the compaction program of research project have also been compared with those of various case histories
Morphometry of Villous Membrane of Placenta at high and low Altitudes
Background: This cross sectional study was designedto compare the histomorphological characteristics ofhuman placenta at low and high altitudes, with specialreference to villous membrane. It was a cross sectionalcomparative study, conducted at Anatomy department ofArmy Medical College Rawalpindi, from October 2002 toApril 2003.Methods: Forty placentae were collected from normalcases at Rawalpindi (low altitude/ LA) and 40 werecollected at Skardu (high altitude/HA). Samples ofplacental tissue were taken and processed. Histologicalstudy was done in H & E and PAS stained sections.Detailed morphology of terminal villi and villousmembrane was studied. Thickness of villous membranewas measured which has not been mentioned in previousstudies.Results: Mean value of villous membrane thickness inLA and HA groups was 2.188 + 0.023 m and 2.027 + 0.020m respectively. The quantitative difference betweenmean thickness of villous membrane in LA and HA groupswas statistically significantConclusion: Thickness of villous membrane wassignificantly less in high altitude group probably showingadaptive changes to overcome the effect of reducedoxygen tension
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