Study of mass transfer correlations for intensified absorbers in post-combustion CO2 capture based on chemical absorption

Process intensification (PI) technologies such as rotating packed beds (RPBs) could reduce the size of absorber used in post-combustion CO2 capture (PCC) based on chemical absorption processes by about 12 times compared to absorber with standard packed beds. However, mass transfer correlations for predicting effective interfacial area and liquid film mass transfer coefficient in RPBs are limited in literature and their prediction accuracy against experimental data is yet to be compared. This need is addressed in this study by evaluating the performances of different correlations through comparison with experimental data. Of all the correlations assessed, it is found that Lou et al. [1] and Tung and Mah [2] correlations give reliable estimate of the effective interfacial area and liquid film mass transfer coefficients respectively

The Prospects and Challenges of Market Segmentation Practice in the Equipment Leasing Industry of Nigeria 2000-2013

Efficiency in the blending of the marketing mix elements all things being equal is higher among firms whose operations are based on market segmentation principles. Given this, the study appraised the level of adoption of the principle of market segmentation in the equipment leasing industry of Nigeria as it assessed this industry in relation to the nation’s macro economic development. Data base of the research are questionnaire and oral interviews. Findings are that the volume and value of transactions in the equipment lease industry is small thus lessors are involved in scramble merchandizing rather than in specialized operational fields of equipment leasing, lessors have poor knowledge of the needs and operational environments of the lessees hence adoption rate to changes in the market is poor, among others. This work recommends the recapitalization of the market as a means of strengthening the financial base of lessors for specialized operation as well as introduction of policies that have the capacity of encouraging cross boarder lease transactions in Nigeria

Impact of population growth on biodiversity loss in boki agro-ecological rainforests, cross river state, nigeria

In today's world, the rapid growth of human populations, who rely on forest resources as their primary source of income, is a major source of concern. The impact of population increase on biodiversity loss in the Boki rainforest in Nigeria's Cross River State was investigated in this study. The study looked into the causes of rapid population expansion, the proximate causes of deforestation, the effects of deforestation on biodiversity, and the economic values of rainforests to Boki inhabitants. The study gathered information on the factors that contribute to population growth, the pace of biodiversity loss, the causes of deforestation, and the effects of deforestation on biodiversity in the study area. The findings found that a mix of human influences such as rapid population growth, increasing human activities such as lumbering, fuel wood extraction, settlement expansion, agricultural practices, and construction works had aggravated tropical rainforest degradation in the studied area. These factors have aided in the extinction and depletion of important flora and fauna species in the study area. To maintain the Boki rainforests and it’s biodiversity, the report suggests population education, research-based innovative forestry and biodiversity policies, and forest restoration efforts such as community-based forest management

Modelling of a post-combustion CO2 capture process using extreme learning machine

This paper presents modelling of a post-combustion CO2 capture process using bootstrap aggregated extreme learning machine (ELM). ELM randomly assigns the weights between input and hidden layers and obtains the weights between the hidden layer and output layer using regression type approach in one step. This feature allows an ELM model being developed very quickly. This paper proposes using principal component regression to obtain the weights between the hidden and output layers to address the collinearity issue among hidden neuron outputs. Due to the weights between input and hidden layers are randomly assigned, ELM models could have variations in performance. This paper proposes combining multiple ELM models to enhance model prediction accuracy and reliability. To predict the CO2 production rate and CO2 capture level, eight parameters in the process were utilized as model input variables: inlet gas flow rate, CO2 concentration in inlet flow gas, inlet gas temperature, inlet gas pressure, lean solvent flow rate, lean solvent temperature, lean loading and reboiler duty. The bootstrap re-sampling of training data was applied for building each single ELM and then the individual ELMs are stacked, thereby enhancing the model accuracy and reliability. The bootstrap aggregated extreme learning machine can provide fast learning speed and good generalization performance, which will be used to optimize the CO2 capture process

Ground Subsidence Induced by Oil Drilling Process

The process for oil drilling through superficial deposits often results in ground movements. However, because of the rapid sequence of the operations, these movements are hardly noticed or monitored. Oil drilling is generally carried out over drilling slabs or platforms. Such a slab was constructed on a land location close to the Imo River in Niger delta of Nigeria. During the process of drilling over the slab, large depressions around the cellar pits were noticed. This development demanded the lowering of the rig and an investigation into the causes of the movements was initiated. The investigation confirmed the existence underneath the slab of sandy clay overlying badly sorted sandy gravel occasionally interbedded with thin argillaceous seams. The ground water table was high. The mean percentages of sand and gravel in the deposit were 20 and 80 percent respectively. This poor combination of sand and gravel gave rise to instability within the deposit. The drilling process, which had considerable disturbing effects on granular deposits, caused the sand to migrate to fill the interstices formed by the gravel particles with consequent creation of subsurface voids, which were the main contributors to the subsidence

Factors Vitiating Against the Effectiveness Of The Nigeria Police In Combating The Criminal Exploitation of Children And Women

It is estimated that each year close to one million persons are trafficked across international borders. Nigeria has been identified as a major source, destination, and transit for the trafficking of persons, particularly women and children. The women are trafficked mostly to Europe and the Middle East, as well as to North America for the purposes of sexual exploitation. Children are trafficked within Africa and other parts of the world for the purposes of adoption, for domestic and agricultural labor, and for sale of human body parts. Efforts by the government of Nigeria (including enacting new laws, strengthening existing laws and other social control mechanisms, and collaborating with other countries) to combat trafficking and the sale of humans have not yielded appreciable results. Several factors (inadequate policing, corruption within the policing system, relative deprivation of freedoms, mounting social injustices, lack of conventional social opportunities, increasing conflicting social values, gender imbalances in the provision of education and economic opportunities, and the breakdown of social institutions) cause this impasse. This study examines the nature, extent, and development of this phenomenon and attempts to delineate the factors vitiating against Nigeria’s law enforcement and government efforts in combating this particularly troubling international crime. Two policies are possible. The short term would introduce mass education about the danger of human trafficking and strengthen the legal instrument and the capability of the law enforcement system to deal with the problem, and the long term would address the social and economic conditions in Nigeria which sustains the phenomenon

An Assessment of Entrepreneurship Involvement among Undergraduate Students of Cross River State University of Technology, Ogoja Campus, Cross Rive State

The study evaluated entrepreneurship involvement among undergraduate students of Cross River State University of Technology, Ogoja Campus, Cross Rive State. Data was obtained through the administration of a structured questionnaire to undergraduate students with personal business irrespective of the scale. Result indicated that family knowledge and natural ability did not determine students’ entrepreneurship involvement but the need for money, desire to become self-dependence and the desire to be employers of labour. The study identified University entrepreneurship internship programme and parental occupation as main sources of entrepreneurship awareness accruable to university students. Furthermore, fund from parents and personal savings were the main sources of capital used to start a business.  Pearson’s correlation showed a high, positive and significant association between students' involvement in entrepreneurship and income diversification (0.97, P<0.01). Independent samples test indicated that entrepreneurship motivation between male and female students differs (t = 12.767, P<0.05). The study based on the result obtained suggested that the universities in Nigeria should add more valves to their graduate by incorporating into their curriculum elements that enhance the development of entrepreneurial attitudes and self-efficacy. Keywords: Entrepreneurship, Student involvement, Undergraduate students, Source of capita

Performance Evaluation of Native-Kankan Padded Evaporative Space Cooler Using Arduino Mega

Performance evaluation of native-kankan padded evaporative space cooler using Arduino Mega is presented. Materials for fabrication were both locally improvised and conventionally sourced for such as the Nigerian Native-Kankan fibre sponge used as the wet and dry filter pads and expanded polystyrene which is used as thermal insulation material. Dry air from the outdoor surrounding is passed through the soaked Kankan fibre pad using a reverse DC fan and cooled by evaporative means where the sensible heat of dry air is converted to latent heat accumulation in the circulating working fluid. 150Watts solar power was supplied to the constructed cooler for a test run and results showed that the peak temperature drop of 27℃ to 24.5℃ was experienced in the indoor space / cooler exit of the test room facility. The average system COP of 1.224, evaporation rate of 0.066GPH and cooling capacity of 95.23W was achieved from the conducted experiment. The native-kankan dry filter pad reduced the humidity level of cooled air entering the indoor test room cubicle by 2%. A comprehensive cooling load analysis of the test room facility was carried out and the results were applied using sensible heat removal method to achieve cooler size rating of 319.02CFM. All experimental results were collected using Arduino Mega, type K thermocouple sensors and DHT11 humidity sensors installed on the constructed evaporative cooling unit. Keywords: Latent heat; Air conditioning; Relative Humidity, Arduino Mega; Evaporative Cooling; Native-Kankan fibre sponge

Trace element geochemical imprints and multi-path health risk assessment of potentially toxic elements in soils from the polymetallic area of tashan-jatau, northwestern nigeria

The occurrence of Potentially toxic elements (PTEs) in the soil phase may portend environmental, ecological and health-related risks. Hence, this study has combined high-precision geochemical analyses (X-ray fluorescence (XRF) and inductively Coupled Plasma Mass Spectrometry (ICP-MS)), quantitative soil pollution indices and health risk assessment modelling for a holistic and precise assessment of the intrinsic vulnerability of the soil system to contamination. Geochemical analysis showed that the soils are highly enriched with PTEs such as V (mean = 449.5 mg/L), Cr (mean = 529.9 mg/L), Cu (mean = 374.4 mg/L), Sr (mean = 1365.3 mg/L), Zr (mean = 2703 mg/L), Zn (mean = 282.5 mg/L), and Pb (mean = 127.3 mg/L). Quantitative soil pollution assessment (contamination factor and enrichment factor) revealed that besides mining, the distribution and association between trace elements and oxides were from surface environmental conditions (including mobility potential, leaching metal-complexation, weathering and oxidation of parent material). Health risk assessment based on hazard quotient and hazard index revealed that the inhabitants are generally more exposed to risks from toxic elements ingestion than dermal contact and inhalation; the children are vulnerable to risks than adults. The cancer risks from ingestion and dermal contact of As and Cr for both children and adults are relatively higher (> 1.0E−04) than the acceptable range; although the children population seems to be more susceptible to cancer risks due to lower body weight. &nbsp

Multi-element association and regional geochemistry of protoliths in tashan jatau area, northwestern nigeria: implications for gold exploration

Soil geochemical surveys are widely used in the early stages of gold exploration, especially in areas with poor outcrops and thick overburden. Fifty-one (51) soil samples were collected in duplicate with the aim of analyzing them geochemically and determining the gold grade through panning and weighing methods. The geochemical results were subjected to multivariate statistical treatment through Factor analysis and Pearson correlation matrix. Four factors were generated from the PCA. These are Factor 1: Cu-Sr-Nb-Ba-La-W-Pb-Zr, suggesting sulfide mineralization that is related to granitic rock while Factor 2 has Au with a low to negative correlation with Mo and Nb suggesting a second phase of intrusion-related activity which must have emplaced gold in this area. Factor 3 is made up of W-Pb suggesting a second sulfide mineralization distinct from the first. While Factor 4 gives a single element factor, Hg. Single-elementt maps were constructed to show the element dispersion in the catchment. In general gold concentrations in this study is erratic and attain a high of 0.67ppm and 0.90g/t. The study delineates the northwestern part of the catchment to be the most prolific in terms of gold potential and shows that the granitic batholiths are the most primary gold-hosting lithology. &nbsp