Shear Thickening and Scaling of the Elastic Modulus in a Fractal Colloidal System with Attractive Interactions

Dilute oil dispersions of fractal carbon black particles with attractive Van der Waals interactions display continuous shear thickening followed by shear thinning at high shear rates. The shear thickening transition occurs at $\dot\gamma_{c}\approx 10^{2}-10^{3}s^{-1}$ and is driven by hydrodynamic breakup of clusters. Pre-shearing dispersions at shear rates $\dot\gamma>\dot\gamma_{c}$ produces enhanced-modulus gels where $G' \sim \sigma_{pre-shear}^{1.5-2}$ and is directly proportional to the residual stress in the gel measured at a fixed sample age. The observed data can be accounted for using a simple scaling model for the breakup of fractal clusters under shear stress.Comment: 5 pages, 5 figures; v2: treating low shear rate date separately; edited title; reworked figure

Carboxymethylation of Icacina trichantha Oliv.Tuber Starch and Its Use as a Viscosifier and Fluid Loss Control Agent in Water Based Mud

Starch from a non-food wild plant- Icacina trichantha oliv.tuber was extracted, characterized and chemically modified by carboxymethylation to produce two new derivatives of two different degrees of substitution. The derivatives were used in the preparation of water based muds. The rheological and filtration properties of these new muds were compared to those of muds prepared with the underivatized native starch and a commercial drilling starch using viscometric and fluid loss methods. Experimental results showed that the new muds have better filtration control behavior and viscosity than those of the native and commercial drilling starches. The values of flow index of the new muds were found to be less than 1.0, showing non-Newtonian and Pseudoplastic flow behavior of drilling muds. Yield stress of the muds increased with the modification. Viscosity decreased with increasing shear rate, showing shear thinning behavior of drilling muds. The new muds were found to obey the API models for static filtration as well as Power law and Herschel–Bulkley models for fluid rheology. Keywords: Icacina trichantha oliv.;Carboxymethyl starch; drilling mud; filtration; rheology

Characterization of Petroleum Hydrocarbons in Post-Burn Crude Oil-Spilled Soils, Gokana, Rivers State, Nigeria

In the Niger delta, crude oil spilled soils are burned as a means of decontaminating the impacted soils. Gas chromatography - flame ionization detector (GCFID) analyses were performed on oil residues extracted from burnt spilled oil soil samples to facilitate detailed chemical composition and characterization of petroleum hydrocarbons. The concentrations of aliphatic hydrocarbons (AHCs) from C13 to C36 were low and range from 363.4 to 439.6 mg/kg, with hydrocarbons burning ≤ C12 and the monocyclic aromatics – BTEX not detected in all the samples. Polycyclic aromatic hydrocarbon (PAH) concentrations, which ranged from 3236.6 to 4190.0 mg/kg, were significantly high and constituted from 88.26 to 91.25% of total petroleum hydrocarbon compositions in the burnt spilled oil soil samples. Petroleum hydrocarbon distribution profiles for the AHCs and PAHs were similar for all the samples and indicated similar alteration source. The compositions of AHCs were generally low, between 1.13 and 11.18%, while compositions of PAHs varied considerably from 0.17 to 30.50%. The composition of the 5-6 ring PAHs were between 3.94 - 4.65 times more than the 2-4 ring PAHs. From these results, the burning of spilled oil soils extensively degraded the AHCs and volatile low molecular weight aromatic hydrocarbons and generated significant amounts of 5-6 ring PAHs, some of which are carcinogenic

How Careers Advice and Guidance can Facilitate Career Development in TVET Graduates: The case in Nigeria

This study examined the current state of careers advice, guidance, and counselling (CAGC) services and programs in the technical, vocational education, and training (TVET) system of Nigerian higher education institutions (HEIs). This was to determine how well current CAGC services and programs foster students’ career development, aspirations, and choices. Forty-eight participants, who were members of the Nigerian National Board for Technical Education (8 participants), guidance counsellors (6), university TVET teachers (18), career experts from the National Directorate of Employment (7), and newly employed TVET graduates (9), volunteered for the study. A purposeful sampling procedure was adopted to recruit participants. Data were collected using a semi-structured interview approach, and we employed a thematic design for the coding and analysis of the transcribed data. The study found no CAGC services and programs in the TVET system. It is recommended, therefore, that TVET systems should focus on providing career development enhanced learning rather than schooling only by revising the curriculum to include programs and activities that promote CAGC activities and programs

Occurrence and sources of aliphatic hydrocarbons in soils within the vicinity of hot mix asphalt plants in Obigbo and Igwuruta Areas of Rivers State, Nigeria

This study investigated the occurrence and sources of aliphatic hydrocarbons (AHCs) in soils within the vicinity of hot mix asphalt (HMA) plants. Soil samples were collected from two HMA plants and analysed with gas chromatography - flame ionisation detector (GC-FID). Sample collection was from both surface (0-15 cm) and subsurface (15-30 cm) soils at an increasing distance of 10 m from the HMA plants while the control samples at both depths were collected at 1 km away from the plants. The AHCs concentration (nC9-nC38) in soils from both HMA Plants ranged from 8.16 - 433.04 mg/kg and 5.91-177.83 mg/kg for surface and  subsurface soils respectively while the concentration in the control samples ranged from 5.97 - 23.95 mg/kg and 2.52 - 13.31 for surface and subsurface soil respectively. The sources of the AHCs were determined using isoprenoid ratios, carbon preference index (CPI) and maximum carbon chain (Cmax). The isoprenoid ratios and CPI values of the samples closer (< 20 m) to the HMA plants were < 1 and < 2 respectively indicating anthropogenic inputs. Samples > 20 m from the HMA plants showed mixture of both anthropogenic and biogenic sources.Keywords: Asphalt Plants; Soil; Aliphatic hydrocarbons; Pristane; Phytane

Serum lipid and glucose concentration in relation to some physiological varibles in college students from Nnewi, Nigeria

Background: Serum lipid and glucose levels are largely determined by and or related to certain physical, physiological and biochemical parameters/variables. This study therefore, is aimed at determining the levels of serum lipid and glucose and the relationship between the serum lipid and glucose concentrations and the physical and physiological parameters/variables of apparently healthy individuals. Method: The blood samples of twenty-five medical students in the age range of 20 and 25 years were analyzed, for the serum glucose, total cholesterol (TC), triglyceride (TG), and high-density lipoprotein cholesterol (HDLc) levels after overnight fast, and LDLc calculated.Result: The mean serum glucose, HDLc, TC and LDLc were not significantly different in females and males students. The serum TG was however significantly lower in females than in the males (90.22 ± 25.17 vs. 116.93 ± 21.54 mg/dl;

A decade study of the incidence and clinical analysis of ectopic pregnancy at a tertiary hospital in Eastern Nigeria

Background: Ectopic pregnancy (EP), a condition where a fertilized egg grows outside a woman’s uterus, is a fertility- and life-threatening gynecological condition. This study aimed at determining the incidence of EP, clinical presentation, gestational age at presentation, risk factors and treatment modalities.Methods: This study was conducted at St. Charles Borromeo specialist hospital, Onitsha, Nigeria (January 2009 to December 2018). Information were obtained from the hospital’s medical records as retrieved from various wards. Data were analyzed using IBM SPSS, version 23, then presented as percentage in tables and figure.Results: Out of 13,402 pregnancies recorded in this study, 119 were EPs giving an incidence of 0.89%. 105 case notes were included in this study since they met the inclusion criteria. Majority of the women belonged to the age group of 26-30 years. Patients with EP presented more between 7-8 weeks of gestational age (40%), though 7.6% were unsure of their last menstrual period. 80 EP cases (76.2%) were ruptured while 25 (23.8%) were unruptured. The ectopic gestation occurred most at the ampulla (51.4%) and more at the right side (66.6%) than the left (33.4%). Pelvic inflammatory disease (30.4%) followed by prior abortion (20.0%) were major predisposing risk factors. The most common clinical presentations were abdominal pain (92.38%), amenorrhea (57.14%) and vaginal bleeding (51.42%). 85.7% had salpingectomy, 9.5% were medically managed.Conclusions: EP remains a major gynecological emergency. Diagnosis before rupture could offer an opportunity for a successful medical management, thereby; minimizing morbidity and mortality

Serum Lipid and Glucose Concentration in Relation to Some Physiological Varibles in College Students From Nnewi, Nigeria

Background: Serum lipid and glucose levels are largely determined by and or related to certain physical, physiological and biochemical parameters/variables. This study therefore, is aimed at determining the levels of serum lipid and glucose and the relationship between the serum lipid and glucose concentrations and the physical and physiological parameters/variables of apparently healthy individuals. Method: The blood samples of twenty-five medical students in the age range of 20 and 25 years were analyzed, for the serum glucose, total cholesterol (TC), triglyceride (TG), and high-density lipoprotein cholesterol (HDLc) levels after overnight fast, and LDLC calculated. Result: The mean serum glucose, HDLc, TC and LDLc were not significantly different in females and males students. The serum TG was however significantly lower in females than in the males (90.22 \ub1 25.17 vs. 116.93 \ub1 21.54 mg/dl; P< 0.05). Furthermore, females are significantly lower in weight than the males (61.2 \ub1 6.91 vs. 69.96 \ub1 9.30 kg; P< 0.05). Significant correlations were also recorded. Conclusion: The results presented showed that the slight difference seen in males and females was a factor of growth and diet and activity.Introduction :S\ue9rum lipide et niveau du glucose sont en grande partie d\ue9termin\ue9s par ou li\ue9s aux certains physique physiologique et variables/param\ue8tres biochimiques. Donc, l'objet de cette \ue9tude est de d\ue9terminer les niveaux de s\ue9rum lipide et du glucose et le rapport entre le s\ue9rum lipide et concentration du glucose et des variables/param\ue8tres physiques et physiologiques des individus apparemment en tr\ue8s bonne sant\ue9. M\ue9thodes : La prise de sang de vingt cinq \ue9tudiants en m\ue9decine dans la tranche d'\ue2ge de 20 - 25 ans ont \ue9t\ue9 \ue9tudi\ue9s pour le s\ue9rum glucose, cholest\ue9rol total (CT) triglyc\ue9ride (TG), et les niveaux de la densit\ue9 \ue9lev\ue9e du cholest\ue9rol lipoprot\ue9ines (HDLc) apr\ue8s un je\ufcne d'une nuit, et LDLc calcul\ue9. R\ue9sultats : Le s\ue9rum glucose, HDLc, TC et LDLc moyen n'\ue9taient pas sensiblement diff\ue9rents chez des \ue9tudiants du sexe f\ue9minin et masculin. Le s\ue9rum TG toutefois \ue9tait sensiblement inf\ue9rieur chez le sexe f\ue9minin et le sexe masculin (90,22+- 25,17 contre 116, 93+-21,54mg/dl ; P<0,05). Par ailleurs sexe f\ue9minin sont sensiblement inf\ue9rieurs en poids plus que chez le sexe masculin. (61,2+-6,91 contre 69,96+-9,30kg : P<0,05). Des corr\ue9lations importantes ont \ue9t\ue9 \ue9galement not\ue9es. Conclusion :À travers des r\ue9sultats, nous notons que la diff\ue9rence l\ue9g\ue8re vue chez le sexe masculin et le sexe f\ue9minin \ue9tait un facteur d'activit\ue9, d'alimentation et de la croissance