Effect of granite dust on the performance characteristics of kernelrazzo floor finish

This study is part of an on-going research on the durability performance of kernelrazzo, a type of terrazzo floor finish. It investigated the effect of partial replacement of the coarse aggregate with granite dust on the compressive strength, water absorption capacity and density of kernelrazzo. Two mix ratios (1:3 and 1:4), varying aggregate replacements of marble chipping with burnt palm kernel shells amounting to 0%, 25%, 50%, 75% and 100%, varying percentage replacements of all coarse aggregates with granite dust amounting to 0%, 10%, 30% and 50% were used. Cost comparisons were also made. Test results showed that the compressive strength of kernelrazzo increases up to a maximum of 30% coarse aggregate replacement by granite dust for both mixes for 0–50% replacement of marble chippings with palm kernel shells. For 75–100% marble chippings replacement, the compressive strength increases with increasing amount of granite dust. The water absorption capacity and density (upto 30% of granite dust) decrease and increase, respectively, with increase in percentage of granite dust. The cost of kernelrazo decreases with increase in the percentage of replacement of coarse aggregates with granite dust, except for 100% marble chipping replacement. It was recommended that to produce a good kernelrazzo floor finish in terms of strength, durability, density, water absorption capacity and cost, the overall coarse aggregate should not contain more than 50% of palm kernel shells for 1:4 and 1:3 mix ratios with a maximum of 30% aggregate replacement with granite dust. ? 2004 Elsevier Ltd. All rights reserved

Recycling fine sandcrete block waste (FSBW)as fine Aggregate in the production of sandcrete Block

The study investigated the use of Fine Sandcrete Block Waste (FSBW) as fine aggregate in the production of sandcrete blocks with a view of controlling waste and decongesting block molding production sites. Standard sandcrete blocks of size 450mmX225mmX225mm were prepared from a mix ratio 1:6 (cement: fine aggregate) containing sand and FSBW as fine aggregates. The sand was partially replaced by FSBW in the mix within the range 0% - 90% in steps of 10%. The blocks were cured for 28 days and then tested for compressive strength. The physical properties of both the sand and FSBW were also determined. The results of the study revealed that the physical properties of FSBW compares favorably with those of conventional sand with the exception of water absorption. It further showed that the density and the compressive strength of the tested blocks decrease as the percentage replacement of sand with FSBW increases. The density of the blocks varied linearly with the compressive strength. Blocks prepared for mixes having 50% FSBW content or less were found to satisfy the minimum recommended compressive strength of 3.45N/mm2 (NIS 87:2000)

Development of CdSe thin films for application in electronic devices

Thin films of cadmium selenide (CdSe) have been deposited on fluorine-doped tin oxide (FTO)-coated glass using potentiostatic electrodeposition method. The suitable range of deposition potentials for the formation of stoichiometric layer of CdSe was established using cyclic voltammograms. The films have been characterised using X-ray diffraction (XRD), Raman spectroscopy, optical absorption, scanning electron microscopy, atomic force microscopy and photo-electrochemical (PEC) cell techniques. XRD results show that the deposited films are polycrystalline in nature having hexagonal structure with preferred orientation along (002) plane. PEC study reveals that the films have n-type electrical conductivity. The optical bandgap of the film have been estimated to be 2.00 and 1.80 eV for as-deposited and heat-treated layers respectively when grown at a cathodic potential of 1,972 mV. The electronic quality of the electrodeposited CdSe layers was also tested using the device structure glass/FTO/n-CdSe/Au which produced Schottky diodes with rectification factor of 102.9, reverse saturation current of ~372 nA and threshold voltage of ~0.15 V. The potential barrier observed for Au/n-CdSe interface is >1.10 eV

Computer and Hardware Modeling of Periodically Forced

Numerical simulation results for the dynamics o

Quantum vibrational resonance in a dual-frequency driven Tietz-Hua quantum well

We investigate the response of a quantum particle in the Tietz-Hua quantum potential driven by biharmonic fields – a low and a very high frequency force. The response is characterized by the occurrence of a maximum in the first-order transition probability amplitude, |s|2 , under the influence of the applied fields. It is shown that in the absence of the high-frequency component of the applied fields, |s|2 shows a distinct sequence of resonances; whereas an increase in the amplitude of the high-frequency field induces minima in |s|2. However, the |s|2 maximum occurs in the low-frequency regime where it may be considered otherwise weak in the presence of a single harmonic force

Assessment of Concrete Durability in Buildings: the Effects of the Quality of Cements Available in Lagos, Nigeria

This paper presents an investigative research that aims to find the effects of the cements available in Lagos, Nigeria on the durability of concrete within the study area. This is in an attempt to stem the rate of building failures in Lagos, Nigeria. The physical, the mechanical and the microstructural properties of the cements have been determined and compared with the standard properties as specified in relevant standards. 150mm cubes have been cast with these cements and all the sources of aggregates within the study area. Laboratory findings have discovered that all the cements investigated have fallen short of the expected strengths specified in standards but the labelled brands had values close to the strength standards but the unlabeled ones have fallen far short of the standard strength. The chemical analysis has complied with standard requirements except for their loss on ignition (LOI) values and the chemical properties have been complemented by the microstructural morphology as determined with the Scanning Electron Microscope (SEM) though the unlabeled brands have tendencies for alkali silica reactivity due to higher levels of alkali present in them. In assessing their performance in concrete, the concrete cube strength has met the expected 20MPa except for the unlabeled brands that have fallen a little short of it. The effects of these cements have been discovered to be very significant on the concrete durability within the study area. It is thereby recommended that the Nigerian regulatory agencies on cements make more efforts in order to ensure that cement manufacturers in Nigeria improve the quality of their cement brands in order to standard strength specification. All cements should be temporarily used as a 32.5 strength class, despising the labelled 42.5, pending when the manufacturers would fully comply their products to standard. Copyright © 2019 Praise Worthy Prize S.r.l. - All rights reserved

A Comparative Analysis of Batching by Weight and Volume towards Improved Concrete Production

Batching of concrete is generally the proportioning of the different constituents of concrete before mixing which could be by weight or volume. Mix-design justified by trial test is the best method to achieve a concrete of desired properties. Standardized prescribed concrete (SPC) mix-design is mostly adopted in mass concreting to high strength concreting applications in most developing nations. British standards accept volume batching for SPC only in mass concrete (<15 MPa) but batching by weight for normal and higher strength concrete. Structural concrete like in storey buildings requires at least a normal strength concrete (>20 MPa) recommended to be batched by weight. Designs batched by volume have been identified as the most commonly used method in concrete production in Nigeria and most developing nations, especially by medium to small scale construction firms due to the very high cost of employing batching plants. This research work developed a modified volumetric batch mix-design that will be equivalent to SPC design mix batched by weight in normal and higher strength concrete. The physical properties of the constituent concrete materials, fine aggregate, 12 and 19 mm sized coarse aggregates were determined. The strength of SPC mix of ST2, ST4, and ST5 to British standard were determined when batched by weight and their volume equivalents mix-design batch determined. The strengths of these SPC mixes were batched by volume and their weight equivalent batch-design determined. A relationship was determined between both batching mixdesign methods for all the prescribed mixes and strengths using the binder-aggregate and coarsefine aggregate ratios, such that the preferred weight batching design mix could be achieved by a modified mix-design batched by volume. This study concludes that concrete mix-design batched by weight is superior to when batched by volume and the desired design batching by weight could be achieved by generating a modified mix-design-batch by volume. This will improve the quality of concrete storey buildings in most developing nations

Detection of Molecular Markers of Antimalarial Drug Resistance in Plasmodium Falciparum from South-Western Nigeria

The widespread of drug resistant Plasmodium falciparum has led to a rise in malaria- associated mortality most especially in sub-Saharan Africa. Falciparum malaria was confirmed by microscopic examination of Giemsa-stained blood samples of patients who presented with fever in selected State Hospitals in Ogun State, Southwestern Nigeria. Molecular methods were employed to detect the markers of resistance of P. falciparum to Chloroquine, sulphadoxine/pyrimethamine,and artesunate in Ogun State, Southwestern Nigeria. DNA was extracted from patient blood using the QiaAmp DNA Blood Minikit extraction method. Nested Polymerase Chain Reaction followed by Restriction Fragment Length Polymorphisms (PCR/RFLP) were used for the detection of P. falciparum chloroquine resistance transporter (Pfcrt), P. falciparum multidrug resistance 1 (pfmdr1), P. falciparum dihydrofolate reductase (Pfdhfr), P. falciparum dihydropteroate synthase (Pfdhps) and P. falciparum sarco/endoplasmic reticulum calcium-dependent ATPase (SERCA) PfATPase6 genes. Pfcrt (K76T ) Pfmdr1 (mdr 1 ) Pfdhfr (S108N), and Pfdhps (K540E) resistant genes were detected among the isolates while resistant SERCAPfATPase6 gene which codes for artemisinin resistance was not detected in the population

Ethanol Extract of Blighia Sapida Stem Bark Show Remarkable Prophylactic Activity in Experimental Plasmodium berghei-Infected Mice.

This work explores the antiplasmodial potential of ethanol extract of Blighia sapida (Lin. Sapindaceae) in chloroquine (CQ)- resistant Plasmodium berghei (ANKA strain)–infected mice. Chloroquine-resistant (ANKA) strain of P berghei was inoculated intraperitoneally into Swiss albino mice. Mice were treated orally for 4 consecutive days, before and after inoculation (prophylactic, suppressive, and curative models) with graded doses of the plant extracts with Artemether-Lumefantrine (Coartem) as control. Prophylactically, the extract showed a remarkable activity in the chemosuppression of P berghei parasites (

AMINO ACID COMPOSITION AND ANTI-TYROSINASE ACTIVITY OF METABOLITES FROM EDIBLE Pleurotus SPECIES FOR THEIR NUTRITIONAL AND THERAPEUTIC POTENTIAL

Mushrooms are being extensively researched due to their nutritional value and medicinal importance. The genus Pleurotus is the second most cultivated mushroom and is known for its high nutritional value, therapeutic properties, taste, flavor, as well as their application in biotechnology and environmental study. Also, tyrosinase is prevalent in most living organisms. The enzyme catalyzes the oxidation of monophenols to ortho-quinones in a two-step reaction process. This study was aimed to assess the amino acid composition and anti-tyrosinase activity of metabolites obtained from edible Pleurotus species. Assessment of the nutritional content and inhibitory studies of mushroom tyrosinase produced from four Pleurotus strains was carried out using high-performance liquid chromatography (RP-HPLC). The results of the study showed that seventeen different amino acids were identified in the crude and partially purified protein metabolites. Also, the crude extract metabolite had the highest quantity of amino acids than the partially purified. The highest and lowest amino acids value Glutamic acid (1343.26 µmol/mL) and valine (0.34 µmol/mL). The anti-tyrosinase inhibition studies of the four Pleurotus strains showed varying results from significantly inhibitory effects to slightly inhibitory effects on mushroom tyrosinase. The highest inhibition was 14.86% (Pleu-W), while the lowest inhibition was 51.42% (Plof-30) respectively. The high point of this study is that the Pleurotus species contains a significant number of amino acids and also, they possess good anti-tyrosinase activity. Therefore, these are a good source of nutritional and therapeutic metabolites and these can be explored further for their nutritional and medicinal importance to man