1,266 research outputs found
Preparation and characterization of nanocrystalline Ba(Ti0.96SnxZr0.04-x)O3 ceramic
Nanocrystalline powders of Barium titanate (BaTiO3 or BT) and Ba(Ti0.96SnxZr0.04-x)O3 (BTSZ1, BTSZ2, and BTSZ3) [x=0.02, 0.03 and 0.04] have been synthesized by a combination of solid-state reaction and high energy ball- milling technique (HBM). The effect of increasing Sn content on the microstructure and dielectric properties of the ceramics were studied. X-ray diffraction patterns show cubic and tetragonal symmetry without secondary phase. Sn4+ and Zr4+ ions entered the perovskite-type cubic structure and led to an increase in the lattice parameters. The average crystallite size has been calculated using Scherrer formula. Using Scherrer, the crystallite size of the (110) peaks of the pure BT is 31.2 nm and that of BTSZ1, BTSZ2, and BTSZ3 are 42.7, 37.9 and 42.3 nm respectively. The FESEM results indicated a variation of grain size from 144.53, to 89.28 nm for the pure BT, BTSZ1, BTSZ2, and BTSZ3, which show a decrease in grain size as Sn doping increases. Frequency dependence of dielectric permittivity and loss studied in the range temperature and frequency range 30-400oC and 40 Hz–1 MHz, respectively, for BT, BTSZ1, BTSZ2, and BTSZ3 show a normal ferroelectric phase transition behavior. The corresponding dielectric constant and loss at room temperature show that BTSZ2 has the highest dielectric constant and loss of 1671 and 1.6 respectively. The high dielectric constants and relatively lower loss tangent values meet the current demand for device miniaturization in the electronics industry.Keywords: BT-BTSZ ceramics; high energy ball milling; XRD; FESEM; dielectric propertie
Investigation into The Filterability of Raw Sugars from Different Geographical Regions of The World
This study was carried out at Al khaleej Sugar Refinery in Dubai, United Arab Emirates. The study aimed to find out the correlation between the filterability and slurry resistance values of raw melt liquor in the carbonation sugar refinery and the raw sugar quality.
The investigation utilized 5 raw sugar samples collected from various regions of the world comprising three quality groups namely; Low Pol sugar (LP) from Thailand, Very High Pol sugar (VHP) from Brazil , South-Africa , Sudan , India , and Very Very High Pol sugar ( VVHP ) from Brazil.
The filterability and the slurry resistance tests were used as the main determining factors for the evaluation. The filterability of refined sugar (considered as 100 % ) was used as a reference value for comparison.
The results of the experiments showed that the filterability of (L P) raw sugar was only about 20% from that of refined sugar. Whereas the filterability values for (VHP) and (VVHP) sugars ranged between 40% to 80% from that of refined sugar.
In addition, the slurry resistance values for VHP and VVHP sugars in the laboratory were 0.76 and 0.64 respectively compared to 0.74 and 0.48 in the refinery production line.
It was also observed that there is a close similarity between laboratory filterability and slurry resistance with the actual refinery filtration process which suggests that the laboratory filterability and slurry resistance tests could be used as tool to predict the behavior of the refinery filtration process for similar qualities of raw sugar
Validity of Finite Element Method: Analysis of Laminated Composite Decks Plates Subjected to in Plane Loading
To verify the accuracy of the present technique, buckling loads are evaluated and validated with other works available in the literature. Further comparisons were carried out and compared with the results obtained by the ANSYS package and experimental results. The good agreement with available data demonstrates the reliability of the finite element method used
Stability of Thin Laminated Decks Plates Under Plane Compressive Loading
It was found that symmetric laminates are stiffer than the anti – symmetric one due to coupling between bending and stretching which decreases the buckling loads of symmetric laminates. The buckling load increases with increasing aspect ratio, and decreases with increase in modulus ratio. The buckling load will remain the same even when the lamination order is reversed. The buckling load increases with the mode number but at different rates depending on the type of end support. It is also observed that as the mode number increases, the plate needs additional support
The Influence of Residual Linamarin in Dried Cassava Peel Meal on Carcass Yield and Gut Characteristics of Weaner Rabbits
A feeding trial was conducted to assess the effects of residual linamarin on carcass yield and gut characteristics of rabbits fed diets containing sun dried cassava peel meal (CPM). The experiment was conducted using a completely randomized design involving four diets of 16% crude protein. The CPM was included at 0, 30, 35 and 40% levels. Rabbits used for the studies were fed for 42 days and were all serially slaughtered fortnightly. During each slaughter, two rabbits were randomly selected, starved overnight and slaughtered. They were skinned, eviscerated and the carcasses cut up into parts and weighed. The guts were separated into; small intestine, large intestine, caecum and appendix. Each of the visceral parts were weighed and their length recorded. The results showed that chest and back were significantly (P<0.05) affected by dietary treatments. Also the carcass yield obtained over time of slaughter indicated a significant (P<0.05) effect on the weight of the back. The time of slaughter x diet interaction effect showed no significant difference on all parameters. The results of the guts showed that, dietary influence were only obtained on the weights of the caeca (P<0.001) and appendix (P<0.05). There were significant diferences on the  weights of large intestine (P<0.05), caeca (P<0.01) and appendix (P<0.001) over the period of slaughter. There is also a highly significant (P<0.001) difference in the length of the caeca. The results of the interaction effect on time of slaughter x diet for all the visceral parts (guts) measured showed a highly significant (P<0.001) interaction effect on the weight of the caeca and that of the small intestine (P<0.05). The studies indicated that despite sun drying, linamarin, a cyanogenic glucosides still has some potential toxic effects as manifested on the carcass yield, large intestine, caeca and appendix. It is thus, suggested that prolonged feeding of CPM must be investigated to safeguard against poisoning. It might also affect caecotrophy in the caeca and the absorption of nutrients in the appendix. Keywords: Linamarin, gut characteristics, dried cassava peels, rabbit
OPTIMIZATION OF BIODIESEL PRODUCTION FROM DANIELLA OLIVERI OIL SEED USING WASTE SNAIL SHELL AS HETEROGENEOUS CATALYST
Biodiesel has gained support and recognition as a fuel to replace fossil fuel which has caused a lot of damage to the environment. In search of locally cheap raw materials that could be used for biodiesel production at a cheaper rate. An investigation was carried out with Daniela oliveri oil seed and waste snail shells as raw materials. One step alkaline transesterification was conducted to produce the biodiesel. Snail shell was used as a source of CaO heterogeneous catalysts by calcination process at 9000C for 5 h. Four process parameters were optimized; methanol to oil ratio 7:1, reaction temperature 500C, catalyst concentration 2.0 wt% and reaction time 60 min to obtained high yield of biodiesel 77% from the oil. The fuel properties of the produced biodiesel from D.oliveri oil were compared with the ASTM standard and found within the requirements
The search for mitochondrial tRNALeu(UUR) A3243G mutation among type 2 diabetes mellitus patients in the Nigerian population
The study aimed to compare the incidence of the pathogenic point mutation A3243G in the gene tRNALeu(UUR) indicating sub-type 2 diabetes mellitus conducted within the Nigerian population with that reported in other populations. 112 patients diagnosed with type 2 diabetes (T2D) mellitus according to the World Health Organization criteria were selected based on family history and re-evaluated for associated disorders from the diabetic clinics in the Northern part of Nigeria. The mtDNA of these patients was extracted and the tRNALeu(UUR) gene screened for A3243G by PCR-RFLP method. Probands with maternal history were further investigated for other mutations using PCR-sequencing methods. None of the 112 patients were found to carry the A3243G mutation in the mitochondrial tRNALeu(UUR) gene in the homoplasmic or in the heteroplasmic form. However, C3254T was identified in two of our patients. This mutation was reported to be associated with gestational diabetes and linked with population from sub-Saharan Africa. The A3243G mutation in mitochondrial tRNALeu(UUR) is not a frequent cause of maternal diabetes in the Nigerian population contrary to other reported populations. However, further screening of an enlarged selected study group is necessary to fully determine the prevalence of this mutation in this population. This further search will help to fully appreciate the prevalence of maternal inheritance and diabetic deafness (MIDD) as extensively reported in other populations.Key words: Maternal diabetes, mitochondrial gene, maternal Inheritance and diabetic deafness, Nigeria, sub-Saharan Africa
Structural and dielectric properties of Ba(Ti0.96Sn0.01Zr0.03)O3 perovskite nanoparticles fabricated by mechanochemical synthesis route
Lead free Nanocrystalline BaTiO3 doped with Sn and Zr is prepared by a combination of solid-state reaction and high energy ball milling (HBM) technique in a temperature range 30–150 °C, over a frequency range 40 Hz – 1 MHz. A single-phase nanocrystalline sample with ABO3 type of perovskite structure with cubic symmetry was confirms by XRD diffraction. The crystallite and grain size determined from Scherrer equation and intercept method are 38.2 nm and 46.13 nm respectively. FE-SEM images show samples are dense and have different microstructures with certain amount of porosity. A grain size of 46.13 nm is obtained by using linear intercept method. Room temperature (RT) variation of ′and tan as a function of frequency of the modified BT system has also been studied. Variation of dielectric properties with frequency shows the usual behaviour of dielectric materials i.e decrease of the value of ′ with the increase of frequency. A dielectric anomalies is observed corresponding to phase transitions viz tetragonal to cubic (− ) at 70oC. These effect can guide to design the nanostructure for various practical applications of MLCC
Prescribers’ Adherence to Treatment Guidelines for Uncomplicated Malaria in Primary Health Centres in Bayelsa State, Nigeria
Background: Malaria, though preventable and treatable, remains a disease with unacceptably high mortality in Nigeria. Effective and prompt treatment of uncomplicated cases reduces progression to severe disease, development of drug resistance, and cuts the costs of the disease.Objective: To assess adherence by prescribers to recommended treatment (based on National Treatment Guideline) for uncomplicated malaria in primary health centres (PHCs) in the eight Local Government Areas (LGAs) of Bayelsa State, Nigeria.Methods: A retrospective review of case notes and prescription sheets for suspected malaria cases treated at 28 PHCs within a year of data collection was done. Relevant data about the prescribers, the patients, and the antimalarial drugs prescribed were collected and analyzed as appropriate.Results: A total of 2,303 case notes of patients attending PHCs were examined over the study period. A high proportion of malaria (1422, 61.7%) was observed among the 2,303 cases. The median age (years) of adults was 28.0 (IQR = 14), and for children of 0-5, 2.0 (IQR = 2.17). Majority of those treated were females (792, 55.7%) and children (967, 68.0%). Artemisinin-based combination therapies (ACTs) were the most prescribed antimalarials (961, 67.6%), followed by artemisinin monotherapies in 23.8% of cases. Proportion of treated cases of malaria that could be considered rational across the LGAs was 67.6%.Conclusion: Adherence of prescribers to National Treatment Guidelines of uncomplicated malaria in PHCs in Bayelsa State was below the required standard, with continued usage of obsolete agents, such as artemisinin monotherapies. Training on case management for prescribers at this level of care is urgently needed.
Keywords: Antimalarial drugs, Malaria, Primary Health Centres, Community Health Workers, Bayelsa State
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