TANZANIA JOURNAL OF SCIENCE AND TECHNOLOGY

Designing PostGIS Database System with Fuzzy Theory to Support Accessibility Tools for Urban Pedestrians

Sun, 31 Dec 2023 00:00:00 +0000

The combination of fuzzy logic and crowdsourcing can be a powerful tool for generating geospatial data for pedestrians with mobility challenges in urban areas. Although potentially useful, information about the accessibility of paths that is generated through crowdsourcing is susceptible to a high degree of imprecision. Spatial data management is required for such systems, which supports the management of uncertain data. Fuzzy theory allows us to model ambiguous information. To fill this gap, an improved method based on a fuzzy relational PostGIS database (FPostGIS) is proposed. The method includes extensions to represent imprecise data within an entity-relationship (ER) data model specifically tailored for path accessibility, and a set of steps for the derivation of FPostGIS from this extended ER model. According to the case study, this methodology has been applied in the design and development of decision support application within the Maps for Easy Paths (MEP) project. This application stores and retrieves accessibility information about a particular path and allows performing spatial operations and analysis inside the database.

Abundance and Distribution of Microplastics in Fish and Sediments from Coastal River Watersheds of Dar es Salaam, Tanzania

Macarius Mtega, Joel , Fidel — Wed, 10 Jan 2024 00:00:00 +0000

Different reports indicate that microplastics have been environmental pollutants which are engulfed by aquatic organisms also are carriers of other toxic chemicals. This study aimed to characterize and determine the spatial distribution of microplastics in sediments and fish in Dar es Salaam. The study had to indicate the extent of plastic pollutants in the urban watersheds. Fish and sediment samples were collected from river watersheds and ponds. Gastrointestinal parts were digested using 10% KOH and incubated at 65 oC for 24 hours while sediment samples were extracted using the floatation method in 4 M NaOH and 3 M NaI solutions. The identity of microplastics was determined by an attenuated Fourier transform infrared spectrophotometer. The concentrations of microplastics were 94 ± 24 particles/kg for fish samples from River Msimbazi watershed ponds and 46 ± 16 particles/kg for fish samples from River Mzinga watershed ponds. The concentrations of microplastics in sediments were: 64 ± 35 particles/m2 for the River Mzinga watersheds and 25 ± 18 particles/m2 for River Msimbazi watersheds. The microplastics observed were polypropylene, polyethene, polyurethane, polyamide, polyvinyl chloride, polyethene terephthalate, and polytetrafluoroethylene. The microplastics were in the form of fragments, sponges, and fibres. The results confirmed that fish living in river watershed ponds in Dar es Salaam were exposed to microplastics and that sediments had microplastics. Further studies need to be performed to find out micro-pollutants adsorbed by microplastics in the river watersheds.

The capability of Artificial Neural Networks as a Model for Predicting Total Electron Content (TEC): A Review

Daudi — Sun, 31 Dec 2023 00:00:00 +0000

The results of investigations from a complete analysis of ANN application on Total Electron Content (TEC) prediction are presented in this paper. TEC is important in defining the ionosphere and has many everyday applications, for example, satellite navigation, time delay and range error corrections for single frequency Global Positioning System (GPS) satellite signal receivers. The total electron content (TEC) in the ionosphere has been measured using GPS. GPS are not installed in every point on the earth to make global TEC measurements possible. As a result, it is crucial to have certain models that can aid to get data from places where there is not any in order to comprehend the global behavior of TEC. Neural Network (NN) models have been shown to accurately anticipate data patterns, including TEC. The capacity of neural networks to represent both linear and nonlinear relationships directly from the data being modeled is what makes them so powerful. The survey from literature reveals that, Levenberg-Marquardt algorithm is preferred and used mostly because of its speed and efficiency during learning process, and that ANN showed a good prediction of TEC compared to the IRI model. As a result, NNs are suitable for forecasting GPS TEC values at various locations if the model's input parameters are well specified.

Reuse of Sludge from Wastewater Treatment Plants in Agriculture: Problem of Heavy Metals in Moshi Municipality Wastewater Treatment Plant

P. B Nyangwe, Alexander — Sun, 31 Dec 2023 00:00:00 +0000

Municipal wastewater treatment plants (WWTPs) have the potential to play a significant role in a circular economy by adopting the principles of reduce, reuse, and recycle (3R). While the primary goal of a WWTP is to decrease the pollution in sewage, this process also produces various potentially valuable byproducts such as treated effluent, biogas, and sludge. The challenge in recycling beneficial nutrients from sludge to agricultural soil primarily arises from the presence of heavy metals, partly due to their toxicity and environmental persistence. This study aimed to examine the concentrations of specific heavy metal contaminants (Cd, Zn, Fe, Cu, and Cr) in sludge from the Moshi municipal WWTP, which is slated for use as fertilizer. The samples underwent analysis using an Atomic Absorption Spectrophotometer (AAS). The examination of sewage sludge revealed a pH average indicating an acidic condition at 5.93 ± 1.05, while iron averaged at 53.32 ± 3.66 mg/kg and copper varied between 0.10 and 3.43 mg/kg, with an average of 1.63 ± 1.18 mg/kg. Environmental assessment involved the application of three pollution indices—Contamination Factor (CF), Index of Geo-accumulation (Igeo), and Pollution Load Index (PLI). These indices collectively confirmed the absence of contamination in the sludge regarding these elements. However, ensuring the elimination of environmental risks and evaluating potential impacts on human and animal health regarding the use of sludge from treatment plants necessitates comprehensive studies across various treatment facilities in the country, considering the chemical composition of these sludges.

Human Health Risks from Exposure to Heavy Metals in Water from Great Ruaha River Serving Domestic Purpose in Pawaga Division

Gustavin , Alexander — Wed, 10 Jan 2024 00:00:00 +0000

River water and banks could be very busy with varied activities ranging from farming to small industrial activities and other domestic household activities. The present study aimed at investigating the potential human health risks from selected heavy metal contaminants in Ruaha River water at the Kilolo division. To assess potential human health risks the concentration data for six heavy metals (Fe, Mn, Cu, Pb, Zn, and Cd) during the wet and dry seasons from four (4) villages were analyzed using Atomic Absorption Spectrophotometer. The observed mean concentration of heavy metals during the wet season is in the following order: Fe > Zn > Cu > Mn > Pb > Cd > Al. During dry season is in the following order: Fe > Cu > Zn > Mn > Al > Cd= Pb. The HQing of Cd ranges from 0.000 – 9.000 while Pb ranges from 2.143 – 32.143. The maximum carcinogenic risk (CR) from ingestion of Cd was 9.429 × 10-4 and Pb was 4.714 × 10-3. According to risk assessment standard these values are in grade five and six respectively. About 54.2% of the analyzed samples are at grade seven which is extremely high-risk position, while the rest are at high-risk side. Though most levels did not exceed critical values for human health risk from heavy metals, there is still a potential human health risk from chronic exposure to low heavy metal concentrations due to long-term exposure and potential metal interactions. Results of this study inform water pollution remediation and management efforts designed to protect public health in polluted urban area waterways common in rapidly developing regions.

The Usage of social media in Creating Land Degradation Awareness in Rombo District, Kilimanjaro Region - Tanzania

Hendry Hermenegild, Nima Shidende — Sun, 31 Dec 2023 00:00:00 +0000

The environment is the fundamental for all living things, and land conservation is of greater apprehension for the sustainable economic development. To attain higher level of land conservation there should be greater effort in creating awareness to people on land degradation conservation. The study aimed to find out the usage of social media in creating land degradation awareness. Specifically, the study intended to: find out the causes of land degradation, identify the status on the usage of social media for land degradation awareness, likely determine the type of social media frequently used for land degradation awareness. The field work covered Rombo district in the Kilimanjaro region Tanzania, where five administrative wards were scrutinized, to mention: Tarakea, Motamburu, Olele, Mahida, and Ngoyoni. Data was collected employing household survey and interview and analysed using descriptive and thematic analysis techniques. The results show that the usage of social media that can be used in creating land degradation awareness includes providing education through media for peoples to understand relationship between human activities and land quality, providing user-friendly tools for knowledge sharing, enabling users to create, edit and add online contents, engaging discussions through social media on environmental issues as well as reporting on land degradation. Further, social media can be used to create land degradation awareness to peoples in Rombo district by 59%. It was concluded that, public campaign program to enhance awareness on land degradation should be strengthened through the usage of social media for sustainable land usage.

Anaemia among schoolchildren; A narrative review

Elina Jacob Maseta — Sun, 31 Dec 2023 00:00:00 +0000

Anaemia is a significant problem in the developing world, such as Sub-Saharan Africa (SSA), with the greatest burden of disease experienced in children. Although extensive research on anaemia has been done among the pre-schoolers, less is documented about schoolchildren. Thus, the current review intends to summarise recent data on the prevalence and risk factors of anaemia among schoolchildren aged 5-18 years across SSA for planning mitigating interventions. A review was conducted on published English articles in Sub-Saharan countries providing estimates on anaemia prevalence and risk factors using databases from PubMed and Google Scholar from January 2010 to April 2021. A total of 41 articles were identified for review. Based on eligibility criteria, 18 articles were included in the current review. The review showed that the prevalence of anaemia among schoolchildren ranged from 11% (Ethiopia) to 83% (Nigeria). Generally, infection (56%), eating less protein and vegetables (33%), age (22%) and sex (16%) of the child were the significant risk factors for anaemia among schoolchildren. The current review established that anaemia is directly associated with infection, less consumption of protein and vegetables, age and sex of the child. Effective public health strategies such as biofortification of food are needed to improve micronutrient intake among older children.