The Computation method of Solid Ducted Rocket (SDR) is a complex problem. It needs to effectively solve the two mixing and combustion processes, and is also affected by many factors such as the overall scheme and propellant type. In order to find a suitable method, physical model, simplified hypothesis, control equation, turbulence model, combustion model, etc. were investigated. Subsequently, calculations were carried out based on the Vanka model, and finally the results of pressure, temperature and combustion efficiency were obtained. The results show that the proposed method is practicable, and the accuracy and efficiency are ideal. Combustion efficiency is only 77.4%, and the Vanka model must be further improved by the air and gas intake modes. The results can provide reference for relevant research.

Brain Tumour is an abnormal cell formation inside the brain. They are mainly classified as benign and malignant tumours. Magnetic Resonance Imaging (MRI) is used for effective diagnosis of brain tumour. An automated method for detection and classification of brain tumour is preferred as analysis of MRI manually is a difficult task for medical experts. The proposed method uses Adaptive Regularized Kernel based Fuzzy C-Means Clustering (ARKFCM) for segmentation. A combination of Support Vector Machine (SVM) and Artificial Neural Network (ANN) is proposed for detection and classification of brain tumour based on the extracted features. A dataset of 94 images is considered for validation of the proposed method which resulted in an accuracy of 91.4%, Sensitivity of 98%, Specificity of 78% and Bit Error Rate (BER) of 0.12. Comparison of the proposed method is carried out with other conventional methods and the results are tabulated.

The basic difference between a sustainable aesthetically positive urban environment and an aesthetically negative one is in the way its component installations are rendered. The aesthetic positivity (AP) or aesthetic negativity (AN) of the whole is dependent on the aesthetics of the little parts that constitute it. Although may be functional, many electrical installations in Nigeria still lack considerable aesthetics mostly due to lack or laxity in the knowledge or practical application of basic design theories and principles. This study therefore examined how the application of design principles and theories used in graphic design can apply in electrical and design installations as a way of fostering a more aesthetic, yet functional and sustainable environments in developing West African countries using aesthetics as a key driver. Adopting a descriptive approach supported with direct observation, with a sample size of 320, respondents were purposively sampled in selected cities in Nigeria. The study showed a significant relationship between the application of graphic design theories and improved environmental aesthetics through the rendering of attractive-functional electrical/design installations. It also revealed that improved aesthetics of electrical/design installations limits negative interference which improves sustainability/safety in the built environment, hence serving as an abatement tool or technology for the alleviation of AN. This study therefore established the significance of the application of design theories and principles in achieving a more aesthetic, functional and sustainable environment, from the professionals’/ practitioners’ perspective.

In this paper theoretical studies have been performed on a multijunction GaInP/GaAs based tandem solar cell. The top GaInP cell and the bottom GaAs cell were investigated separately. At an operating temperature of 300K, the current matching condition is fulfilled when the top cell and bottom cell base doping concentration and thickness are set to 5x1015/cm3, 1µm, and 2x1017/cm3, 0.127µm respectively. For the purpose of the investigation, a wide operating temperature range was chosen from 25ºC to 100ºC. The optimized tandem solar cell structure having a thickness of 1.847 microns is found to have VOC=2.2996V, ISC=0.0136Amp/cm2, FF=87.61% and ɳ=27.4% under AM1.5G one sun illumination. Studies have also revealed that when the cells are analyzed separately the current mismatch is less significant at low temperatures with the difference becoming notable at higher temperatures. Simulations of the solar cell were performed using PC1D.

Wireless sensor networks (WSN), when applied to the field of water quality monitoring and management, has the potential to bring numerous benefits as compared to traditional methods since it is accurate, reliable in remote areas and in the tough condition such as during rainy seasons, and less costly. With the ever-growing application of Internet of Things (IoT) and technology in general, sensor devices have become less expensive and widely used in many applications that require remote monitoring. In this work, we present an innovative and secure water monitoring and management system using remote sensor prototype, which has been developed to monitor physiochemical parameters including pH, Turbidity, Temperature, and Dissolved Oxygen. Qualitative research methods were used for gathering system requirements through questionnaires and interviews conducted in Pangani water basin authority, in the United Republic of Tanzania. Documents were also reviewed to provide secondary knowledge. Furthermore, the system was developed using Dynamic System Development Methodology (DSDM). Firstly, the proposed system prototype is able to provide real-time measurements accurately. Secondly, the proposed system uses Advanced Encryption Standards to provide a secure transmission and storage of data transmitted from remote sensor nodes to a central database system. Thirdly, the web application was developed for data visualization using tabular and graphical formats. Lastly, the system prototype provides decisions support on quality of water present in Pangani river basin by evaluating sensor measurements and sends SMS alerts once the measured value is above the recommended standard values.

The determination of strength properties i.e., compressive strength (CS) is essential to estimate the load at which the concrete members may crack especially in aggressive environment. The paper reports an experimental investigation on deterioration of used engine oil (UEO) soaked concrete with respect to its strength properties. Also, it is found that this deteriorating effect is lessened with partial replacement of silica fumes (SF). The CS analysis was done with a water-concrete ratio of 0.49 with nine percentage replacements of SF (0, 5, 10, 15, 20, 25, 30, 35, 40 and 45) with water curing and UEO soaking. The soaking in two different liquids was essential in order to throw light on the detrimental effects of UEO on the CS of concrete. The results of the experiments showed that 20% replacement of SF in concrete was optimum to attain maximum CS. A mathematical model based on Abrams’ law has been developed to evaluate the strength characteristics of concrete subjected to UEO soaking. The developed model facilitates the prediction of CS based on curing time in water and soaking time in UEO and also the quantity of SF used. The accuracy of the developed model is evaluated and good agreements with the ground truth values are found.