Energy Efficiency Technologies for Buildings: Potential for Energy, Cost, and Carbon Emission Savings

Buildings are a significant energy consumer and are responsible for an increasingly large percent of worldwide greenhouse gas emissions, currently between 30 and 40 percent. Energy efficiency presents unique opportunities for building owners to reduce their environmental footprint and add value through cost savings, tax deductions, and increased market value. An analysis of 183 samples of efficiency measures in seven technology categories found that 74% of efficiency investments had a positive net present value. Building automation system and chiller plant improvements had the highest mean energy and carbon dioxide savings per square foot. Additionally, building automation systems had, on average the highest return on investment, approximately $800 above the cost of implementation per one thousand square feet. Only building envelope modifications had a negative mean return on investment. Building automation system upgrades avoided an average of 350 pounds of CO2e for every dollar spent, reducing a building’s total carbon footprint by as much as 28%. The results suggest that a significant opportunity for cost, energy, and emission savings is available across all technology categories

A comparative study of the physical and mechanical properties of coarse aggregates produced in Ogun state

This study investigates the compliance of the physical and mechanical properties of granites produced in some parts of Ogun State to relevant codes and standards. The desire to carry out the study was borne by personal on – site experience that single size aggregates produced in some parts of Ogun State do not conform to grading requirements specified in relevant codes and standards. Samples of 9.5mm, 12.5mm, 19mm and 25mm aggregates were collected from four different quarry sites spread across the state. T he Samples were tested for their Specific Gravities, Water Absorptions, Moisture Contents, Aggregates Impact Value and Aggregates Crushing Value in accordance to the relevant standards. Test results reveals that all the samples conform to relevant codes an d standards . It was therefore concluded that although the aggregates do not conform to grading specification b ut the physical and mechanical properties of all the aggregates meet the specifications in relevant codes and standards. Key words: Evaluation, Physical, Mechanical, Properties, Aggregates and Standard

Investigation of the physical and mechanical properties of Shea Tree timber (Vitellaria paradoxa) used for structural applications in Kwara State, Nigeria

This study investigated the physical and mechanical properties of Shea Tree timber (V. paradoxa) for structural use obtained at different areas of Kwara State, Nigeria. Physical properties of the samples like moisture content, specific gravity and density was evaluated and the mechanical tests were tensile strength, modulus of rupture, modulus of elasticity, compression, shear and hardness. Results show that, the density of the specie varied from 1.05 to 1.48 (g/cm3), and specific gravity varied from 0.98 to 1.39. For the mechanical properties, the results revealed that at 18% moisture content and 80% grade stress, mean MOR of 28.91(N/mm2), mean MOE of 9,108 (N/mm2), compressive strength parallel to grain of 24.7 (N/mm2), compressive strength perpendicular to grain of 8.99 (N/mm2), shear strength of 2.01 (N/mm2), and tensile strength parallel to grain of 16.15 (N/mm2). Finally, according to BS 5268-2 (2002) the specie was characterised into strength classes between D50 and D70. The results obtained showed that Shea Tree is a hardwood and suitable to be used for structural engineering purposes.Keywords: Vitellaria paradoxa, Physical properties, Mechanical properties, Structural timber, Green Constructio

Heat And Mass Transfer Of Magnetohydrodynamic (Mhd) And Dissipative Fluid Flow Past A Moving Vertical Porous Plate With Variable Suction

An investigation was carried out on the radiation effect on unsteady heat and mass transfer of MHD and dissipative fluid flow past a moving vertical porous plate with variable suction in the presence of heat generation and chemical reaction. The dimensionless governing equations for this model were solved analytically using perturbation method. The effects of various parameters on the velocity, temperature and concentration fields as well as the Coefficient of skin-friction, Nusselt number and Sherwood number were presented graphically and in tabulated forms. Keywords: Chemical reaction, Unsteady, Porous medium, MHD, Radiation, Mass transfer and Heat sourc

Development of a horizontal three bladed windmill with vortex tubes

Researchers have been continuously searching for the most readily available means of producing electricity without any negative effect on the environment. Renewable source of energy like solar energy, hydro electric energy, biomass and wind energy has been considered as the alternative. Wind energy among others is rated the best renewable sources of energy because it’s level of environmental friendliness. In this paper, a horizontal windmill was designed, fabricated and its performance evaluated with two types of vortices and without a vortex. The component parts of the mills are towel, blades, shafts, base, tail vain and vortex. During the design of the windmill, consideration was given to the size, area of the blade and the blade material that produce maximum speed. The performance evaluation was carried out to compare the performance of the mill with the solid vortex, gap vortex and without vortex. The result of the evaluation reflects that the solid vortices have the highest wind speed irrespective of time of the day and with an optimum wind speed of 5.04 m/s. Also, the wind mill performed at a higher efficiency with the vortex compare to when it was running without vortex. &nbsp

Design of intelligent braking system

It is anticipated that a variety of cars with diversified features that include anti-lock braking system (ABS), traction control system (TCS), antiskid Steering, collision warning system (CWS) will be more commercially produced to satis@ the consumer needs in the near future. This is parallel to the trend of current technology of manufhcturing smart cars and the &sires of people who always want to have comfortable and safe ride in their vehicles. Mower this type of vehicles can fit much better into the intelligent highway that Malaysian government is planning to have in the near future. Consequently, there is a need to modify the current conventional braking system so as to make it work automatically. This paper considers the use of intelligent controller to achieve the above objective. To ensure high speed of system response, the DSP controller TMS320C24x with - fuzzy algorithm is used in the implementation of this new device. Results of simulation studies using the MATLAB have demonstrated the feasibility of this new system under investigation

Design And Implementation of Dsp-Based Intelligent Controller For Automobile Braking System

An intelligent braking system has great potential applications especially, in developed countries where research on smart vehicle and intelligent highways are receiving ample attention. The system when integrated with other subsystems like automatic traction control, intelligent throttle, and auto cruise systems, etc will result in smart vehicle maneuver. The driver at the end of the day will become the passenger, safety accorded the highest priority and the journey optimized in term of time duration, cost, efficiency and comfortability. The impact of such design and development will cater for the need of contemporary society that aspires to a quality drive as well as to accommodate the advancement of technology especially in the area of smart sensors and actuators. The emergence of digital signal processor enhances the capacity and features of universal microcontroller. This paper introduces the use of TI DSP, TMS320LF2407 as an engine of the system. The overall system is designed so that the value of inter-vehicle distance from infrared laser sensor and speed of follower car from speedometer are fed into the DSP for processing, resulting in the DSP issuing commands to the actuator to function appropriately

Performance evaluation of the deconvolution techniques used in analyzing multicomponent transient signals

Deconvolution is an important preprocessing procedure often needed in the spectral analysis of transient exponentially decaying signals. Three deconvolution techniques are studied and applied to the problem of estimating the parameters of multiexponential signals observed in noise. Both the conventional and optimal compensated inverse filtering approaches produce data which are further analyzed by SVD-based autoregressive moving average (ARMA) modeling techniques. The third procedure is based on homomorphic filtering and it is implemented by fast Fourier transform (FFT) technique. A comparative study of the performance of the above deconvolution techniques in analyzing multicomponent exponential signals with varied signal-to-noise ratio (SNR) is examined in this paper. The results of simulation studies show that the homomorphic deconvolution technique is most computationally efficient, however, it produces inaccurate estimates of signal parameters even at high SNR, especially with closely related exponents. Simulation results show that the optimal compensation deconvolution technique is indeed a generalized form of the conventional inverse filtering and has the potential of producing accurate estimates of signal parameters from a substantial wide range of SNR data

Population dynamics and size stratification in 75-day old bred juvenile African Catfish (Clarias gariepinus, Burchell, 1822) raised in concrete tanks

Cannibalism and aggressiveness exhibited more frequently by Catfish has been linked to disparity in sizes, sex ratio and/or stocking density, this study was carried out to investigate population dynamics and size stratification within the Clarias population bred in 4m x 4m x 1m artificial concrete tanks. A total of two hundred and fifty (250), 75-day old juveniles were randomly selected and measured for live body weight and linear body measurements which include, Total Length (TL), Standard Length (SL), Head length (HL), Pre-Dorsal Length (PDL), Dorsal Fin Length (DFL), Pre-Anal Length (PAL) and Anal Fin Length (AFL). Two indices (length-weight relationship and Fulton’s condition factors) were also computed for predictive assessment of future performances and wellbeing of the fish. The fish weight ranged between 3.30g and 20.30g with an overall mean body weight of 10.61 ± 0.28g. Based on the weight, the Sturge’s formula was used to construct nine class intervals of 2.0g width each, with the grouping resulting in disproportionate frequency distribution which was statistically (P<0.0001) significant. Of all the variables measured, weight had the highest variability within the population with a CV of 41.88%, while other measures had Coefficient of Variation of between 13.82% and 16.65%. It was observed that based on the mean body weight of the fish studied, only 6.4% are within the 95% Confidence Interval (CI) of the Mean, while 53.2% and 40.4% are respectively below and above the CI. This stratification and population structure provides a good discriminatory tool in separating the fish into fairly homogenous sizes for further rearing to minimize cannibalism and optimize profit.Keywords: Catfish, Cannibalism, Measurements, Fish wellbein

Parameter estimation of multicomponent transient signals using deconvolution and arma modelling techniques

Parameter estimation of transient signals, having real decaying exponential constants, is a difficult but important problem that often arises in many areas of scientific disciplines. The frequency domain method of analysis that involves Gardner transformation and conventional inverse filtering often degrades the quality of the deconvolved data, leading to inaccurate results, especially for noisy data. An improved method that is based on the combination of Gardner transformation, optimal compensation deconvolution, and signal modelling techniques is suggested in this paper. In this method of analysis the exponential signal is converted to a convolution model whose input is a train of weighted delta function that contains the signal parameters to be determined. The resolution of the estimated decay rates is poor if the conventional fast Fourier transform (FFT) algorithm is used to analyse the resulting deconvolved data. Using an autoregressive moving (ARMA) model whose AR parameters are determined by solving high-order Yule–Walker equations (HOYWE) via the singular value decomposition (SVD) algorithm can alleviate this shortcoming. The effect of sampling conditions, noise level, number of components and relative sizes of the signal parameters on the performance of this modified method of analysis is examined in this paper. Simulation results show that high-resolution estimates of decay constants can be obtained when the above signal processing techniques are used to analyse multiexponential signals with varied signal-to-noise ratio (SNR). This approach also provides a graphical procedure for detecting and validating the number of exponential signals present in the data. Some computer simulation results are presented to justify the need for this modified method of analysis