Dynamic Performance Analysis of Cogeneration Potential in Photovoltaic Power System.

The solar cell junction is susceptible to performance degradation, due to internal temperature rise which is further perturbed by ambient temperature rise. The conversion efficiency of the solar module remarkably drops because of temperature rise. The diurnal module temperature hovers above 60 degrees C. It is possible to keep the conversion efficiency high by water-cooled or air blast equipment. This project is a preliminary study of the impact of temperature variation across seasons on the dynamic performance of photovoltaic power system. The photovoltaic (PV) module was mounted on a test rig at latitude 7 degree on top of physics building Obafemi Awolowo University campus. The output voltage of the PV module was applied to a resistive load and system efficiency performance measured over a period of time covering the dry and rainy seasons. Measurements of ambient temperature, PV junction operating temperature, wind speed, solar irradiance, and power delivered were carried out. A numerical algorithm was developed to analyse the data. The transport medium can store heat energy from the solar module, so that a large amount of hot water can be produced. The results show that this thermal transfer benefit, positions the PV system in good stead, for Microgrid: Cogeneration Energy Efficiency functionality. Keywords: Conversion efficiency, Photovoltaic power system, PV module, Water-cooled equipment, Cogeneration

Evaluation of radar multiple-scattering effects from a GPM perspective. Part I: Model description and validation

A numerical model based on the Monte Carlo solution of the vector radiative transfer equation has been adopted to simulate radar signals. The model accounts for general radar configurations such as airborne/ spaceborne/ground based and monostatic/bistatic and includes the polarization and the antenna pattern as particularly relevant features. Except for contributions from the backscattering enhancement, the model is particularly suitable for evaluating multiple-scattering effects. It has been validated against some analytical methods that provide solutions for the first and second order of scattering of the copolar intensity for pencil-beam/Gaussian antennas in the transmitting/ receiving segment. The model has been applied to evaluate the multiple scattering when penetrating inside a uniform hydrometeor layer. In particular, the impact of the phase function, the range-dependent scattering optical thickness, and the effects of the antenna footprint are considered. © 2006 American Meteorological Society

Evaluation of radar multiple scattering effects in Cloudsat configuration

MonteCarlo simulations have been performed to evaluate the importance of multiple scattering effects in coand cross-polar radar returns for 94 GHz radars in Cloudsat and airborne configurations. Thousands of vertically structured profiles derived from some different cloud resolving models are used as a test-bed. Mie theory is used to derive the single scattering properties of the atmospheric hydrometeors. Multiple scattering effects in the co-polar channel (reflectivity enhancement) are particularly elusive, especially in airborne configuration. They can be quite consistent in satellite configurations, like CloudSat, especially in regions of high attenuation and in the presence of highly forward scattering layers associated with snow and graupel particles. When the cross polar returns are analysed [but note that CloudSat does not measure any linear depolarization ratio (LDR hereafter)], high LDR values appear both in space and in airborne configurations. The LDR signatures are footprints of multiple scattering effects; although depolarization values as high as -5 dB can be generated including non-spherical particles in single scattering modelling, multiple scattering computations can produce values close to complete depolarization (i.e. LDR=0dB). Our simulated LDR profiles from an air-borne platform well reproduce, in a simple frame, some experimental observations collected during the Wakasa Bay experiment. Since LDR instrumental uncertainties were not positively accounted for during that experiment, more focused campaigns with air-borne polarimetric radar are recommended. Multiple scattering effects can be important for CloudSat applications like rainfall and snow-fall retrievals since single scattering based algorithms will be otherwise burdened by positive biases

An Experimental Approach towards PV-Based Solar System Sizing for an Engineering Laboratory

This study aims at providing an experimental sizing procedure for a rooftop PV-based solar power system for an engineering laboratory. This was achieved by monitoring the peak power and energy delivered by an installed 20W solar panel into an 18 Ah battery. Knowledge of the average daily peak power and energy was used to determine the percentage rated capacity available for use and the sun hour. A load consumption comparison was also carried out with and without the connection of a load to inverter. In addition to this, the monitoring of the no-load consumption of the inverter was carried out. This was carried-out to ascertain the contribution of the inverter to the system. With the knowledge of the average daily energy deliverable, sun hour and the no-load power of the inverter, a sample sizing for basic electronic laboratory loads was done. The findings of the study reveals that the average available power is 89.35% of the solar panel rated capacity while the average sun hour is 4.38 h. It has also been shown that an approximate difference of 20 W exists between the power consumption of the load with and without its connection to the inverter. This value (i.e., 20W) has been recorded as the approximate no-load power for the inverter. The sample sizing done has shown that, the solar panel energy requirement of the system with inverter may be considerably higher than that without inverter

Vulnerability analysis of maize farmers to climate risk in Kwara state, Nigeria

There is an increasing concern on the vulnerability of farmers to the impact of climate change. The study analyses maize farmers’ vulnerability to climate risk, it specifically determines their knowledge of climate change; examines their vulnerability; identifies the determinants of vulnerability and their management strategies. Three-stage random sampling was employed. Descriptive statistics, Likert scale, vulnerability index and stepwise regression were the tools of analysis. Result showed 79.5% of the respondents were males while 20.5% were females; 77.5% had no formal education; and their mean farm size was 2.88ha. The majority of the farmers agreed that the climate is changing which is corroborated by the meteorological data analysed. The vulnerability assessment shows that the farmers are vulnerable. The determinants of vulnerability among the farmers were years of experience, information about climate change, sensitivity of farming resource and susceptibility to drought.. The results also showed that farmers do not have the necessary capacity to mitigate against the effect of climate change. It therefore recommends that adequate climatic information, easy access to drought tolerant maize variety should be prioritize in policy making.Keywords: Climate Risk, Kwara State, Maize Farmers, Nigeria, Vulnerability

Evaluation of radar multiple scattering effects in Cloudsat configuration

International audienceMonteCarlo simulations have been performed to evaluate the importance of multiple scattering effects in co- and cross-polar radar returns for 94 GHz radars in Cloudsat and airborne configurations. Thousands of vertically structured profiles derived from some different cloud resolving models are used as a test-bed. Mie theory is used to derive the single scattering properties of the atmospheric hydrometeors. Multiple scattering effects in the co-polar channel (reflectivity enhancement) are particularly elusive, especially in airborne configuration. They can be quite consistent in satellite configurations, like CloudSat, especially in regions of high attenuation and in the presence of highly forward scattering layers associated with snow and graupel particles. When the cross polar returns are analysed [but note that CloudSat does not measure any linear depolarization ratio (LDR hereafter)], high LDR values appear both in space and in airborne configurations. The LDR signatures are footprints of multiple scattering effects; although depolarization values as high as ?5 dB can be generated including non-spherical particles in single scattering modelling, multiple scattering computations can produce values close to complete depolarization (i.e. LDR=0 dB). Our simulated LDR profiles from an air-borne platform well reproduce, in a simple frame, some experimental observations collected during the Wakasa Bay experiment. Since LDR instrumental uncertainties were not positively accounted for during that experiment, more focused campaigns with air-borne polarimetric radar are recommended. Multiple scattering effects can be important for CloudSat applications like rainfall and snowfall retrievals since single scattering based algorithms will be otherwise burdened by positive biases

Willingness of Park Users to Plant Trees in Public Motor Parks to Improve Environmental Condition in Ibadan Metropolis, Oyo State, Nigeria

The effect of global warming and air pollution have shifted more focus to tree planting as a way to combat climate change and improve the environment. Most Nigerian motor parks are polluted; thus, this study investigated the willingness of park users to plant trees in public motor parks to improve park's environmental condition in Ibadan Metropolis, Oyo State, Nigeria using structured questionnaires in six motor parks. Questionnaires were randomly administered to 12 drivers, 5 traders and 3 commuters, per Motor Park, making a total of 120 respondents. Study revealed that 60.8% of motor park users were under the age of 50; 100% of drivers were men, whereas women (70%) dominated trading. Drivers (94.4%) and traders (83.3%) use motor parks on a daily basis, but commuters (66.7%) use the park occasionally. Most of respondents (47.2%), traders (56.7%), and commuters (83.3%) stated that the park’s environment is not conducive (unsuitable). Respondents (85.8%) of motor park users indicated that they want a better environmental condition. Chi-square test reveals a significant relationship between respondents' educational status and perceived environmental condition of the motor park. Logistic analysis indicated that traders (0.183) and commuters (0.236) are less likely to be interested in tree planting. Most Nigerian motor parks have unsuitable environments, tree planting is one potential solution for improving the environmental condition. Relevant authorities should develop policies that encourage tree planting and tree planting should be incorporated and implemented in the design of new motor parks

Medical Support of the Cardiovascular and Metabolic Diseased Patient with Cardiac Pacemaker at the Annual Stage of Observation

Scientific advisers: ass. prof. T. A. Derienko, prof. M. I. YabluchanskyClinical case

Determinants of adoption of vitamin A bio-fortified cassava variety among farmers in Oyo State, Nigeria

The success of any agricultural innovation depends on its adoption by farmers. The study evaluates the determinants of adoption of vitamin A bio-fortified cassava variety among farmers by investigating the level of adoption and determinants of adoption among farmers. Three stages of random sampling procedure were used to select 240 cassava farmers. The data obtained were analyzed with descriptive statistics and a logit regression model. The study revealed that the level of adoption of vitamin A bio-fortified cassava variety is low (38.72%). The study also revealed that access to media, contact with extension agents, access to vitamin A bio-fortified cassava stem, amongst others, are the determinants of adoption of vitamin A bio-fortified cassava variety in the study area. It is therefore recommended that awareness about the new cassava technology should be prioritized to sensitize the farmers, and stems of these cassava varieties should be readily made available to farmers to take advantage of the benefit of the innovation

Willingness to Pay for Environmental Service Functions of Mangrove Forest in Uzere, Delta State, Nigeria

This study was carried out to determine the estimate value of the environmental service functions of Uzere mangrove forest using the Willingness to pay method. We used questionnaires to elicit information on the willingness to pay (WTP) for environmental service functions of Uzere mangrove forest. Contingent valuation approach was used to elicit information on WTP and the socio-economic variables that influence the WTP. Data were obtained from a systematic randomly sampled 300 residents within the three communities in Uzere. The data were subjected to descriptive statistics, F and student’s t-tests, analysis of variance (ANOVA), correlation and multiple regression analyses using statistical package of social sciences (SPSS). The results show that 21.7% of the respondents were willing to pay (WTP) various amounts ranging from N50- N5000 monthly, N50 being the modal value. The mean monthly WTP value is N36.8. This gave an aggregate estimated value of between N147,798.09 and N681,097.19 (US$1= N150) for the environmental service functions of the 2,004.2hectares of Uzere mangrove forest. The semi-log regression equation revealed that the years of residence and occupation are the only socio-economic variables that significantly influenced WTP. The results of this study indicate that the forest is of high value and therefore, there is a need for concerted effort for sustainable management of the mangrove forest. Keywords: Willingness to pay (WTP), ecological services, socio-economic factors,   mangrove forest, Uzere