Polypropylene/carbon nanotube nanocomposite fibers: Process–morphology–property relationships

This study is focused on aligning carbon nanotubes in polypropylene matrix by melt spinning. Two different weight percentages (0.5% and 1.0%) of nanotubes were used for the synthesis of the nanocomposite fibers. The effect of the nanotubes on the crystallization and mechanical behavior of polypropylene as well as the effect of draw ratio on the nanocomposite morphology and properties is also discussed. Correlation of fiber morphology and nanotube alignment was done using differential scanning calorimetry, wide‐angle X‐ray diffraction, and transmission electron microscopy. Significant improvement in tensile modulus and tensile strength were observed, which is characteristic of a highly aligned nanotube system. A substantial vincrease in the onset of decomposition was observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3844–3850, 2007     

Development of engineered natural organic sorbents for environmental applications: 3. Reducing PAH mobility and bioavailability in contaminated soil and sediment systems

The effects of engineered natural organic amendments on two measures of the environmental "availability" of polycyclic aromatic hydrocarbons (PAHs) associated with soil and sediment samples are assessed. Two soils spiked with pyrene alone and a sediment spiked with a mixture of 4 PAH compounds were amended with raw or superheated-water processed peat or soybean stalks, then aged for periods of either 62 or 105 days. The aged soils were then examined with respect to bioaccumulation of spiked pyrene by earthworms (Eisenia foetida), and to its human bioaccessibility as measured by extraction with simulated gastrointestinal fluid. Additions of processed amendments reduced both measures of availability by factors ranging from 7.6 to 27.0 for earthworm bioaccumulation and from 2.3 to 8.8 for gastrointestinal extractability. All PAH compounds spiked to the sediment were reduced to varying extents in their availabilities to E. foetida and leachabilities by water by both processed and raw organic amendments.     

Emerging bio-ethanol projects in Nigeria: Their opportunities and challenges

Despite being a major petroleum producing and exporting country, Nigeria has for a long time imported refined petroleum products for domestic consumption. The country has recently made an entrance into the bio-energy sector by seeding the market with imported ethanol until enough capability exists for the domestic production of ethanol. The Nigerian Biofuel Policy was released in 2007 calling for the domestic production of bio-ethanol to meet the national demand of 5.14 billion litres/year. Some investors have responded by investing over $3.86 billion for the construction of 19 ethanol bio-refineries, 10,000 units of mini-refineries and feedstock plantations for the production of over 2.66 billion litres of fuel grade ethanol per annum. Also, another 14 new projects are in the offing. Of the 20 pioneer projects, 4 are at the conception phase, 8 are in the planning phase, and 7 are under construction with only 1 operational. The potential benefits of the emerging bio-ethanol projects include investment in the economy, employment, energy security and boost rural infrastructure, while the major challenge is land take (859,561 ha). This is the first time an attempt is been made to document the emerging bio-ethanol projects in Nigeria.     

A two-step feature selection method for monitoring tool wear and its application to the coroning process

Coroning is a complex and multi-directional gear finishing process involving metal removal of gear teeth surface, and condition monitoring has not been applied to this process. In order to capture the progress of wear, an acoustic emission (AE) sensor is used, but the large data size of AE requires extensive dimension reduction and feature selection. The conventional method of averaging to reduce the data size may have the risk of losing information as higher frequencies are filtered off. A two-step feature selection method is implemented using class mean scatter criterion and modified relevance/redundancy analysis. This method results in feature dimension reduction and enhances classification performance. It involves first ranking candidate features by calculating their separability. Features which are correlated are then combined to reduce dimensions without averaging. Application of this two-step feature selection technique enables coroning tool wear to be monitored with a classification rate of 98.3 % compared to 94.1 % using conventional feature selection.     

What scope for integrating land management policies,land administration processes and data infrastructures for housing production in Nigeria?

Existing knowledge reveals that land as a resource is not currently managed efficiently and effectively in most countries of the world. One of the factors considered important in understanding the inefficiencies and ineffectiveness is the level of integration between agencies. The objective of this paper is to determine the level of this inefficiency in order to improve our understanding of the inter-relationship between agencies that perform land administration functions. The research methods include a synthesis of past studies and the use of case study approach. It uses as context, Lagos, in Nigeria. This approach involves a mixed method: interviews and online survey. The results revealed limited integration of processes and collaboration of agencies in the management of land for housing production. We conclude that policies are not sufficiently informed by data and there is a noticeable disconnection between agencies, and formulated policies.     

Assessment of greywater reuse as a potential mitigation measure for water shortages and sanitation problems in senior high schools

The study assessed water shortages and its effects on sanitation in Senior High Schools using structured questionnaires involving water availability, water use pattern and perception of greywater reuse. Additionally, an observation of the sanitation situation was done to validate the responses. The study found that water availability was an issue as this caused students to use more than an hour round trip to access water resulting in poor sanitation and hygiene practices. Meanwhile, an average greywater generation rate of 14.5 L per person per day, is always disposed of despite its potential reuse. Greywater reuse was accepted by respondents as 59% proposed reusing it if available for non‐potable applications (94%) such as toilet cleaning and flushing. This is because, there is a significant association between cleanliness of the toilet facilities and usage (P < 0.05). Respondents who declined greywater reuse cited health risks (58%), uncomfortable feeling (37%) and cultural issue (5%).     

Survival pattern of hemodialysis patients in Kumasi, Ghana: A summary of forty patients initiated on hemodialysis at a new hemodialysis unit

To evaluate the survival pattern of hemodialysis patients at a dialysis unit in Kumasi, Ghana, through a retrospective (observational) study. Patients who were placed on hemodialysis at the dialysis unit at Komfo Anokye teaching hospital from October 25, 2006 to December 2007. The patients were followed from initiation of dialysis until December 31, 2007. The overall mortality was 14 (35.9%) on the incident population for the period and that for the first 90 days was 12 (32.4%) patients. Chronic glomerulonephritis was the underlying kidney disease in 35.9%. This was followed by hypertension (19.1%) and diabetes mellitus (15.4%), respectively. Cardiovascular diseases accounted for 42% of mortality. This was followed by septicemia (25%) from the access site and anemia (25%). Fifty percent of the patients were able to afford 20 sessions of hemodialysis before stopping. The most powerful predictors of survival were the duration of hemodialysis (P=0.05) and the number of hemodialysis sessions (P=0.02). Age at initiation of hemodialysis was not significant. First 90-day mortality of patients on hemodialysis is high in poor African countries. This is due partially to the late referral of patients and also the cost of the dialysis treatment. Efforts will have to be made to reduce the cost of the dialysis treatment. Reuse technology (of dialyzer, etc.) should be introduced to cut down the cost of hemodialysis. Peritoneal dialysis should also be introduced for highly motivated patients. Efforts should also be made to reduce the increasing incidence of kidney disease, and finally third-world countries should consider establishing kidney transplantation, that is cost effective.     

Multiscale fiber reinforced composites based on a carbon nanofiber/epoxy nanophased polymer matrix: Synthesis, mechanical, and thermomechanical behavior

Vacuum assisted resin infusion molding (VARIM) was used to produce multiscale fiber reinforced composites (M-FRCs) based on carbon nanofibers dispersed in an epoxy resin. Flexural, interlaminar shear strength (ILSS) and thermomechanical tests are presented for the 0.1 wt% and 1 wt% M-FRCs and compared with the neat fiber reinforced composites (FRCs). Flexural strength and modulus increased (16–20%) and (23–26%), respectively for the 0.1 wt% and 1 wt% M-FRCs when compared to the neat FRCs. ILSS properties increased (6% and 25%) for the 0.1 wt% and 1 wt% M-FRCs, respectively when compared to neat FRCs. The glass transition temperatures (T_g) of both M-FRC samples were 25 °C higher than the neat FRC. Coefficients of thermal expansion (CTE) of the M-FRC samples improved compared to the neat FRC. The improved T_g and CTE properties in the M-FRC samples are attributed to synergistic interactions between the CNF/PNC matrix and glass fibers.