Accurate Bolt Tightening using Model-Free Fuzzy Control for Wind Turbine Hub Bearing Assembly

"In the modern wind turbine industry, one of the core processes is the assembly of the bolt-nut connections of the hub, which requires tightening bolts and nuts to obtain well-distributed clamping force all over the hub. This force deals with nonlinear uncertainties due to the mechanical properties and it depends on the final torque and relative angular position of the bolt/nut connection. This paper handles the control problem of automated bolt tightening processes. To develop a controller, the process is divided into four stages, according to the mechanical characteristics of the bolt/nut connection: a Fuzzy Logic Controller (FLC) with expert knowledge of tightening process and error detection capability is proposed. For each one of the four stages, an individual FLC is designed to address the highly non-linearity of the system and the error scenarios related to that stage, to promptly prevent and avoid mechanical damage. The FLC is implemented and real time executed on an industrial PC and finally validated. Experimental results show the performance of the controller to reach precise torque and angle levels as well as desired clamping force. The capability of error detection is also validated.

Multi-use two wheel tractor operated fertilizer applicator for Coconut cultivation

Unfortunately, it is observed that application of comical fertilizers is low in the coconut sector partlydue to high wages and scarcity of labour.The purpose of mechanization in coconut cultivation is to produce more from existing land. Machineryis a complimentary input required to achieve higher land productivity. Additional benefits to the usermay be associated with a reduction in drudgery of farm work greater leisure, or reduction of risk.Use of manpower for the application of fertilizer is uneconomical due to high labor cost. Thereforepower tiller operated fertilizer applicator for coconut cultivation was designed and constructed. Thismachine is not only useful to broadcast fertilizer on the soil but also to mix it with the soil close to thepalm on the weeded surface.The designed machine consists offertilizer distribution unit and rotary unit. The Maximum spreadingwidth in meter, Machine discharge rate in gr/min and Uniformity coefficient of spray distribution,were considered as criteria for comparison of merits and demerits. The results showed that theMaximum spreading width and Machine discharges rate were 0.7m, and 150 - 230 gr/min, respectively.The cost of production of the designed power tiller operated fertilizer applicator was RS.l 0,000.00

Hydrogeological condition and groundwater quality distribution in the tsunami affected Southern coastal area of Sri Lanka

Groundwater monitoring in the tsunami affected southern coastal Weligama bay area was conductedduring May 2005 to July 2006 to determine the hydrogeological conditions and groundwater quality byselecting 90 dug wells where water level, electrical conductivity (EC), total dissolved solids (TDS)and pH was measured in monthly interval. The Weligama bay area is located in latitudes and longitudesof 80°22', 5°97'. The dug wells are sunk into the permeable quaternary sand deposits in the coastalmargin at Weligama Bay area is very permeable and-hydro-geological conditions are very favorablefor saltwater intrusion.The study helped to prepare groundwater isograph map and the distribution ofEC, TDS and pH mapsusing the GIS package MAPINFO. Groundwater isograph map help to identify groundwater distributionof the coastal area of Weligama. There exist a closed relationship between topographical map &groundwater contour map.The results of the study revealed that the Electrical conductivity of well water in all wells situated inthe Tsunami affected Zone are turned to be saline (EC in average increases from 150011 Siemens perem to around 4000 ~l siemens /cm.). According to the hydrographs prepared during the study period,unconfined quaternary aquifer ground water level intimately related to atmospheric precipitation. Thecharacteristic of the hydrograph provides a conclusion, that the recharge of unconfined ground waterin quaternary aquifer takes place during the period of monsoon rain and quality of ground water dueto tsunami has not changed specially.

Multi-fingered haptic palpation utilizing granular jamming stiffness feedback actuators

This paper describes a multi-fingered haptic palpation method using stiffness feedback actuators for simulating tissue palpation procedures in traditional and in robot-assisted minimally invasive surgery. Soft tissue stiffness is simulated by changing the stiffness property of the actuator during palpation. For the first time, granular jamming and pneumatic air actuation are combined to realize stiffness modulation. The stiffness feedback actuator is validated by stiffness measurements in indentation tests and through stiffness discrimination based on a user study. According to the indentation test results, the introduction of a pneumatic chamber to granular jamming can amplify the stiffness variation range and reduce hysteresis of the actuator. The advantage of multi-fingered palpation using the proposed actuators is proven by the comparison of the results of the stiffness discrimination performance using two-fingered (sensitivity: 82.2%, specificity: 88.9%, positive predicative value: 80.0%, accuracy: 85.4%, time: 4.84 s) and single-fingered (sensitivity: 76.4%, specificity: 85.7%, positive predicative value: 75.3%, accuracy: 81.8%, time: 7.48 s) stiffness feedback

CdS_Substrate_Temperature

All of the characteristic data used are given here

Social capital improvement for protected area management: A study with regarded to Hurulu International Biosphere Reserve.

Recent years, there was a rapid growth of interest in the term social capital in biodiversity conservation as well as protected area management. Hence, this study was conducted to examine existing social networks, to find out how social capital contributes to alleviate poverty and to identify the issues related to social capital improvement related to peripheral communities in “Hurulu” forest in Sri Lanka.The study was carried out in  Habarana  GN division in  Polonnaruwa  district during May to October in 2011. One hundred and fourteen households were selected by using simple random sampling technique. Descriptive statistics as well as developed indices such as poverty and social capital were  used to analysis the data. Out  of  16 functioning societies, seven were active and prominent. Functions of these societies were loans providing, act as an intermediate, provide materials and trainings, help to funeral occasions, protect the “Hurulu”  forest reserve, and maintaining community places.  Maranadara  and Buddhist societies were the most important and strong networks in this area. Some rural societies were not function well.The poverty index for Habarana  GN division was 24.79. Most of organizations were recorded high social capital index, indicating about high potential of poverty alleviation. Based on the findings, social capital is correlated with age and health of the members. The obstacles such as lack of awareness about the importance of the rural societies,  weak governance system, and bureaucratic nature were identified for development of social capital. Increasing social capital is caused to reduce external pressure on protected area as well as increasing local people involvement in conservation management.Key words: Social capital, Hurulu, biosphere reserve, poverty, index, protected area

Synchronizing and protection relay for distributed generators

This document contains an introduction about our final year project which is synchronizing and protection relay for distributed generators. The design procedure, current results and further enhancements are also included in this document

Effects of two litter amendments on air NH levels in broiler closed-houses

Objective High NH3 emissions from poultry houses are reported to have negative impacts on health, welfare and safety of birds and humans, and on the environment. Objective of the present study was to determine the effects of two litter amendments on the NH3 levels in broiler closed houses under hot-humid conditions. Methods Giving a completely randomize design, nine closed houses, each housed 32,500 birds on paddy husk litter, were randomly allocated into two treatment (Mizuho; a bacterial culture mix and Rydall OE; an enzymatic biocatalyst) and control groups. NH3 levels were determined thrice a day (0600, 1200, and 1800 h), at three heights from the litter surface (30, 90, and 150 cm), at 20 predetermined locations of a house, from day 1 to 41. Results Rydall significantly reduced the NH3 level compared to control and Mizuho. NH3 levels at 30 cm were significantly higher than that of 90 and 150 cm. The NH3 levels at 30 cm height were higher than 25 ppm level from day 9, 11, and 13 in Mizuho, control, and Rydall groups, respectively to day 41. NH3 levels at 150 cm height were higher than maximum threshold limit of 50 ppm for human exposure from day 12, 14, and 15 in Mizuho, control, and Rydall groups, respectively to day 33. Being significantly different among each other, the NH3 level was highest and lowest at 0600 and 1800 h. Litter amendments had no significant effects on growth performance. Rydall significantly increased the litter N content on day 24. Conclusion It was concluded that the NH3 levels of closed house broiler production facilities under tropical condition are so high that both birds and workers are exposed to above recommended levels during many days of the growing period. Compared to microbial culture, the enzymatic biocatalyst was found to be more effective in reducing NH3 level