Analytical, Numerical and Computational Multiscale Modelling Techniques for Heterogenous Materials: A Review

oai:ojs2.azojete.com.ng:article/1This paper reviews the analytical, numerical as well as the computational homogenization multiscale modelling schemes for determining the effective material properties for heterogeneous medium at the macroscopic level. It also looked at the limitations of the analytical homogenization techniques in simulating the effective non linear heterogeneous material behaviours (for example the rapid localization of damage and so on) as well as the advancements of the computational techniques in addressing these limitations. In addition, the possible future trends for the computational technique such as the development of a fully coupled micro-macro computational scheme were also discussed. It was concluded that although, the analytical technique was quite popular and straight forward, its inability to capture rapid localization of damage limited its application and that numerical and computational schemes were able to address these limitations as they relied on the establishment of constitutive relations for the macroscopic problems in a numerical form through which the macroscopic problems were constructed and solved in a nested manner

Determinants for hospitalization in " low-risk" community acquired pneumonia

BACKGROUND: A variable decision in managing community acquired pneumonia (CAP) is the initial site of care; in-patient versus outpatient. These variations persist despite comprehensive practice guidelines. Patients with a Pneumonia Severity Index (PSI) score lower than seventy have low risk for complications and outpatient antibiotic management is recommended in this group. These patients are generally below the age of fifty years, non-nursing home residents, HIV negative and have no major cardiac, hepatic, renal or malignant diseases. METHODS: A retrospective analysis of 296 low-risk CAP patients evaluated within a year one period at St. Agnes Hospital, Baltimore, Maryland was undertaken. All patients were assigned a PSI score. 208 (70%) were evaluated and discharged from the emergency department (E.D.) to complete outpatient antibiotic therapy, while 88 (30%) were hospitalized. Patients were sub-stratified into classes I-V according to PSI. A comparison of demographic, clinical, social and financial parameters was made between the E.D. discharged and hospitalized groups. RESULTS: Statistically significant differences in favor of the hospitalized group were noted for female gender (CI: 1.46-5.89, p= 0.0018), African Americans (CI: 0.31-0.73, p= 0.004), insurance coverage (CI: 0.19-0.63, p= 0.0034), temperature (CI: 0.04-0.09, p= 0.0001) and pulse rate (CI: 0.03-0.14, p= 0.0001). No statistically significant differences were observed between the two groups for altered mental status, hypotension, tachypnea, laboratory/radiological parameters and social indicators (p>0.05). The average length of stay for in-patients was 3.5 days at about eight time's higher cost than outpatient management. There was no difference in mortality or treatment failures between the two groups. The documentation rate and justifications for hospitalizing low risk CAP patients by admitting physicians was less than optimal. CONCLUSIONS: High fever, tachycardia, female gender, African- American race and medical insurance coverage are determinants for hospitalization among low risk CAP patients in our study. The average length of stay for in-patients was 3.5 days (3 to 5 days). The cost of in-patient care was about eight times higher than outpatient management. This study supports the recommendation of using the PSI for E.D evaluation of patients in appropriate social settings

Morphogical effects of sodium azide on tomato (Lycopersicon esculentum Mill)

Dry seeds of tomato (Lycopersicon esculentun Mill), varieties T106, T244 and T420 obtained from the Institute of Agriculture Research, Ahmadu Bello University Zaria, Nigeria were treated with sodium azide at concentrations of 1.0, 2.0 and 4.0 mM aimed at determining the effects of the mutagen on the morphological features of tomato. Highly significant differences (

The effects of Diethylsulphate on some quantitative traits of tomato (Lycopersicon esculentum Mill)

Seeds of three varieties of tomato (Lycopersicon esculentum Mill) T106, T244 and T420 obtained from the Institute for Agricultural Research, A.B.U Zaria, were treated with Diethylsulphate (DES) at concentrations of 10, 15 and 30 mM with the aim of determining the effective concentration of the mutagen capable of inducing beneficial mutants in tomato. Highly significant differences (

Spectroscopic and potentiometric studies of Co (II) and Ni (II) complexes with N-(I-Morpholinobenzyl) semicarbazide

The Schiff base complexes of cobalt(II) and nickel(II) were synthesized by refluxing the mixture of ethanolic solutions of the Schiff base and metal(II) chlorides, respectively. The complexes were characterized by gravimetry, spectrophotometry, potentiometry, molar conductance and infrared analyses. The N-(1- morpholinobenzyl)semicarbazide Schiff base and its complex compounds are not soluble in water, slightly soluble in most common organic solvents but are readily soluble in methanol and ethanol. The molar conductance of the cobalt (II) and nickel(II) schiff base complexes determined are in the range 5.38 - 6.03 ohm-1cm2mol-1, suggesting their nonelectrolytic nature. The dissociation constant, pKa, of N-(1- morpholinobenzyl)semicarbazide Schiff base determined is 5.40. The standard Gibb’s free energy of cobalt(II) and nickel(II) N-(1- morpholinobenzyl)semicarbazide Schiff base complexes determined are -70.78KJmol-1 and - 68.06KJmol-1, respectively. The ratio of metal ion to Schiff base determined potentiometrically and spectrophotometrically for the complex compounds is 1: 2. The IR spectrum of the Schiff base shows bands observable in the two Schiff base complex compounds, indicating the coordination of the Schiff base to the cobalt(II) and nickel(II) ions. Key Words: Schiff base, azomethine, benzyldehyde, potentiometry, spectrophotometry, morpholine

Synthesis and characterization of iron (ii) and nickel (ii) schiff base complexes

The complexes of iron (II) and nickel (II) with schiff base derived from benzoin and 2-amino benzoic acid have been prepared. Solubility, melting point, decomposition temperature, conductance measurement, infrared (IR) and UV – Visible spectrophotometric studies were used in characterizing the compounds. The melting point of the schiff base determined is 120oC. The decomposition temperatures of iron (II) and nickel (II) complexes are 152oC and 155oC, while the molar conductance values are 11.2 and 10.7 ohm-cm2mol-1, respectively. The UV-Visible spectrophotometric analysis revealed 1:1 (metal-ligand) stoichiometry for the two complexes. Keywords: Schiff base, conductivity, azomethine, benzoin, spectrophotometry

Synthesis and characterization of N-(I-Morphlinobenzyl) semicarbazide Manganese (II) and Iron (II) complexes

The interaction of ethanolic solution of semicarbazide hydrochloride, benzyldehyde and morpholine yielded N-(I-Morpholinobenzyl) Semicarbazide Schiff base. The Schiff base complexes of manganese(II) and iron(II) were synthesized by refluxing the mixture of ethanolic solutions of the Schiff base and metal(II) chlorides, respectively. These complexes were characterized by gravimetry, spectrophotometry, potentiometry, molar conductance and infrared analyses. The Schiff base and the complex compounds are not soluble in water, slightly soluble in most common organic solvents but are readily soluble in methanol and ethanol. The molar conductance of the manganese(II) and iron(II) Schiff base complexes measured are 3.78 and 6.90 ohm-1cm2mol-1, respectively, indicating their non-electrolytic nature. The potentiometric studies revealed a pKa of 5.40 for the Schiff base. The standard Gibb’s free energy of Mn(II) and Fe(II) Schiff base complexes determined are -65.79KJmol-1 and -60.35KJmol-1, respectively. The ratio of metal ion to Schiff base determined potentiometrically and spectrophotometrically for the complex compounds is 1: 2. The IR spectrum of the Schiff base shows bands observable in the two Schiff base complex compounds, indicating the coordination of the Schiff base to the copper ion. Key Words: Schiff base, azomethine, benzyldehyde, potentiometry, spectrophotometry, semicarbazide hydrochloride, morpholine

THE POTENTIAL OF MAIZE AS PHYTOREMEDIATION TOOL OF HEAVY METALS

This paper shows result obtained from analysis done on some selected heavy metals accumulated in maize planted in contaminated soil for forty two days. The soil (3kg) each was contaminated with 2g of the metals (as FeSO4, CdCO3 and Zn, Mn, Pb, and Cr powder), adapting experimental method of Abd-El Naby 2002 . The results show that essential heavy metals (Fe, Zn and Mn) at day 14 were high with values of 28.275±0.05, 18.210±0.03 and 4.815±0.11 in the experimental and Fe and Zn were high at 28 days with values of 30.21±0.02 and 16.52± 0.01, while at 42 days Fe and Mn were high with values of 33.01±0.00 and 16.88±0.01 respectively. The result for the control soil indicates that Fe, Pb and Zn reduced considerably with values of 3.650± 0.06, 2.006±0.00 and 1.113±0.00 respectively while at day 28 and 42 the same trend was observed to be as day 14. Generally, it was observed that the heavy metals accumulation by the plant in soil for both experimental and control is high in maize. The results show that maize can be used to phytoremediate these metals

Modern software cybernetics: new trends

Software cybernetics research is to apply a variety of techniques from cybernetics research to software engineering research. For more than fifteen years since 2001, there has been a dramatic increase in work relating to software cybernetics. From cybernetics viewpoint, the work is mainly on the first-order level, namely, the software under observation and control. Beyond the first-order cybernetics, the software, developers/users, and running environments influence each other and thus create feedback to form more complicated systems. We classify software cybernetics as Software Cybernetics I based on the first-order cybernetics, and as Software Cybernetics II based on the higher order cybernetics. This paper provides a review of the literature on software cybernetics, particularly focusing on the transition from Software Cybernetics I to Software Cybernetics II. The results of the survey indicate that some new research areas such as Internet of Things, big data, cloud computing, cyber-physical systems, and even creative computing are related to Software Cybernetics II. The paper identifies the relationships between the techniques of Software Cybernetics II applied and the new research areas to which they have been applied, formulates research problems and challenges of software cybernetics with the application of principles of Phase II of software cybernetics; identifies and highlights new research trends of software cybernetic for further research

INTESTINAL HELMINTHIASIS AMONG CHILDREN AND ADULTS IN SOME HOSPITALS IN KANO METROPOLIS

Infection with parasitic helminthes is often recognized as one of the important public health problems in tropical Africa. The majority of this infection occurs in resource-limited settings like Sub-Saharan Africa including Nigeria. The aim of this study was to determine the prevalence of intestinal helminthes among children and adults in some hospitals in Kano metropolis. The study involved a cross-sectional survey of 134 stool samples where 84 were collected from children and 50 from adults. The samples were examined usingdirect wet mount and formol-ether concentration technique. The overall prevalence of intestinal helminth infection observed was 11.2%. In the study, three different parasites were identified. These include Ascaris lumbricoides, Trichuristrichura and Hookworm. In terms of isolation rate, Hookworm was the commonest intestinal helminth observed in children 5 (50%) while Ascarislumbricoides was the most isolated 3 (60%) in adults