In Mozambique, the task of providing infrastructural facilities for the rapidly growing population is enormous. Although the country has unique characteristics that present opportunities for timber construction to thrive, concrete continues to be one of the most used materials in modern construction. However, the concrete industry has a considerable impact on the environment due to production and the raw material consumed. Among the constituents of concrete, sand has been the one in which its exploitation causes the most damage to the environment. An alternative to solve this problem would be the use of fine sandy loam aggregate in the production of concrete. Thus, this research presents the study of the technical feasibility of using fine sandy loam aggregate in the production of concrete. The main study variables were the consistency and mechanical strength of concrete compression. For the production of concrete, two types of gravel of ¾ were used, sandy loam soil, sandy soil and Portland cement. Specimens were manufactured for 4 different mixes, with a reference mix containing cement, sand, gravel and water. To evaluate the performance of the mixes, tests of mechanical resistance to compression were carried out at 7, 14, 21 and 28 days of age. After determining the main physical and mechanical characteristics, promising results were obtained for the mixtures with 25% and 50% substitution, where the axial compressive strength test reached 26.3 MPa and 27 MPa, above the reference mixture of 25.6 MPa. The 100% mix of alternative soil reached an average strength of 25.2 MPa. This same mixture, although having low mechanical strength, has greater consistency, with a slump of ±10 cm. Keywords: concrete, cement, environment, fine aggregate, mechanical strength. DOI: 10.7176/CMR/14-1-02 Publication date: January 31 st 2022
Old Corrugated Container (OCC) is one of the most potential raw material for paper and paperboard manufacture but it has some disadvantage of a continued decrease in the quality of the fiber during the recycling process. It’s caused by decreasing of carboxyl groups when the fibers undergo drying, resulting in decreased ability for swelling, thereby reducing the ability of the bond between the fiber and the fiber strength. Modification of waste paper using laccase enzyme may increase the fiber content of the carboxyl group of waste paper, therefore will increase paper strength. Experiments carried out with the addition of laccase in various dosage paper stock originating from OCC by 5% pulp consistency. 80 g/m Laboratory sheets, was made from stock, then analyzed by tensile index, burst index, wet tensile index, the content of carboxyl groups and SEM analysis. The experimental results showed addition of 50 U/g laccase at OCC giving optimum value for physical properties. Keywords : OCC, laccase, Physical properties, Carboxyl groups, SEM. DOI: 10.7176/CMR/13-3-04 Publication date: November 30 th 2021
In this study, CFs were coated electrochemically with three different monomers (An, EDOT or Py) in different condition such as electrolyte (BA, H 2 S0 4 or NaClO 4 ), solvent (H 2 O as inorganic medium or ACN as organic medium), in presence of foreign material (EBC) and coating method (constant potential and cyclic voltammetry as controlled potential). Obtained CFs were compared with regard to electrical and capacitive and morphological features. In CPE the current flown in system was changed in certain values for each monomer in presence of EBC. But this changing was more for Py than that for the other. In CV experiments, the oxidation potential was increased for PAn and PEDOT when it was decreased for Py. Imax values were changed for each polymer and conditions. According to Randles-Sevcik equation, the electrocoating redox processes in BA-H 2 O were not controlled by diffusion under this conditions. But, all the redox processes carried out in NaClO 4 -ACN electrolyte solution were controlled by diffusion for each polymer coated CFs. In presence of EBC it could be concluded that redox process was controlled by diffusion in BA-H 2 O for PAn and in NaClO 4 -ACN for PEDOT. In presence of 1.8 % EBC. The C DL value was decreased to 4 µF from 6 µF; to 0.7 µF from 1.5 µF; to 1 µF from 3 µF in BA-H 2 O for Pan, PEDOT and PPy respectively. But, it was increased to 11.5 µF from 10.4 µF in NaClO 4 -ACN for PEDOT. Phase angle was in the same trend. The texture coatings were more compact in the presence of EBC in electrolyte solution than that of the absence of EBC for PPy coated CF. The relationship of between the radius of coating and the C DL of the coated CF was proportional. Thus, it may be concluded that the C DL and radius of coating were affected with the presence of different material/compound in electrolyte solution. Keywords: PAn, PEDOT, PPy, presence of EBC, comparison, impedance, texture coating. DOI: 10.7176/CMR/13-3-05 Publication date: November 30 th 2021
Hexavalent chromium ion removal by adsorption using rice husk ash and silica prepared from rice husks obtained locally from rice mill as biosorbents was evaluated as low cost wastewater treatment in this study. Batch equilibrium isotherm experiments were performed as well as effect of dosage and initial chromate solution pH to determine the potentials of the sorbent to remove hexavalent chromate ion from synthetic fed wastewater. Equilibrium isotherm experimental data isotherms were tested with isotherm models (Langmuir, Freundlich and Tempkin models), being best represented by the Langmuir model. Optimum conditions were: dosage = 0.5 g / 200 ml at room temperature and pH o > 6. The equilibrium between adsorbate in the solution and on the adsorbent surface was practically achieved in 2 h. The monolayer sorption capacity was 67.45 mg/g for rice husk silica and 55.98 mg/g for rice husk ash. Estimation of energy of the sorption process revealed chemisorption as the prevailing means of interaction between the adsorbents and adsorbates moieties. The abundance and affordable (cheap) cost of rice husks justifies its use as a precursor in the preparation of rice husk ash and silica as effective adsorbents for chromium removal from industrial effluents. Keywords :Hexavalent chromium, Biosorption, Isotherm, Rice husk ash, Rice husk silica DOI: 10.7176/CMR/13-1-02 Publication date: January 31 st 2021
Novel array arcs- fin heat sink 7×2 with 6×2 multi air jet impingement are presented in this paper by using numerical simulation. Temperature distribution of jets diameter of 5mm and arcs- fin heat sink with variety shapes at constant radius of 45mm are evaluated. Reynolds number ranges from 7000 – 11000. The study has been done at constant Z/d= 6 and constant heat flux =8333.33 W/m 2 . The best shapes of fins has an effective role in improving the rate of heat transfer .In this paper, the design concerned in arcs ships to construct fin geometry. Four concave arcs constricted the shape of fins heat sink for model A. This model has been changed to construct models (B-C-D-E) by reflect two concave arc from it to be convex arc. All five models at the same radius. The five configurations were comparative between each other and the best model comparative with flat plate heat sink. It is observed that model D of heat sink showed best temperature dissipation than the others. The results of this paper can help to select heat sink that meets a design's thermal, Power, packaging and cost requirements (specialized in arcs fins) with array of impingement jet, which is a popular used in cooling electronic devices.
Nowadays, silica gels have developed a lot of interest due to their extraordinary properties and their existing and potential applications in science and technology. Silica gel has a lot of applications such as a desiccant, as a preservation tool to control humidity, as an adsorbent, as a catalyst and as a catalyst support. Silica gel is a rigid three-dimensional network of colloidal silica, and is classified as: aquagel, xerogel and aero-gel. Extraction of amorphous silica from Maize Husk Ash (MHA) was carried out in this study. Silica xerogel was produced by dissolving MHA with alkali solution to form sodium silicate solution and lowering the pH to7 by adding hydrochloric acid to form silica aquagel followed by drying to form silica xerogel. The silica xerogel was characterized using SEM, XRD and FTIR techniques. Silica and mineral contents of MHA and xerogel were determined by EDS, X-ray diffraction patterns revealed amorphous nature of extracted silica. Fourier transform infrared (FTIR) data indicates the presence of siloxane and silanol groups. Silica yield from MHA was 56.32% while moisture content was 2.89% and also the SEM presented appropriated morphological characteristics of the best silica. MHA proved to be a potential low cost raw material for the production of silica gel.
Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic pollutants which get into foods during processing. In spite of this, only a few studies have been carried out on Nigerian delicacies. This study was used to determine the level of PAHs in some smoked fish species namely: clarias gariepenus (catfish) , scomber scombrus (atlantic mackerel) and clupea harengus (herring fish). The fish species were smoked with a local open-fire fish smoking drum and PAHs were determined using the Gas Chromatography (GC) coupled with flame ionization detector (FID). The levels of PAHs were evaluated on the three species of fish. The total values of PAHs have shown that the smoked clarias gariepenus (catfish) , scomber scombrus (mackerel fish) and clupea harengus (herring fish) have 80.01μg/g, 69.94μg/g and 154.08μg/g respectively. Higher values were found in benzo(a)pyrene and lower values found in naphthalene. For benzo(a)pyrene, the values were 9.20μg/g, 2.90μg/g and 40.13 μg/g respectively. For naphthalene, the values were 1.13μg/g, 1.11μg/g and 1.72μg/g respectively. Benzo(a)pyrene, which is highly carcinogenic was found to have the highest concentration in clupea harengus (herring fish) of about 40.13μg/g which is above permissible level. As for the other PAHs, they were all detected in various quantities which resulted to the high level of the total PAHs in the samples. From the study, it was revealed that the open-fire fish smoking pose a health risk for human as it is being contaminated. It is therefore recommended that a low polycyclic aromatic hydrocarbons (PAHs) improved fish smoking kiln should be developed. Keywords: Polycyclic aromatic hydrocarbons, smoked fish, Gas chromatography, Benzo(a)pyrene, Carcinogenic DOI: 10.7176/CMR/13-3-03 Publication date: October 31 st 2021
Most metallic materials lack the adequate surface characteristics to satisfactorily perform intended service functions. In such instance, the surface properties are modified by altering the chemistry, structure and/topology of the top surface of the surface via modification techniques. There exists wide options of techniques for modifying the surface properties and these are well documented in the literature. However, these techniques have different scientific underpinnings controlling them such that it is difficult to use a single mechanism to characterize the techniques. Arising from this, it is imperative that a holistic understanding of the various processes is provided. Therefore, in this paper, research status on the wide range of non-melting technique for surface modification is presented. The presentation discusses the investigation conducted on the various non-surface melting techniques and provides a comparison across the techniques. Recent developments in these techniques are equally presented. Existing challenges and emerging trends in the field are also highlighted. . to chromium carbide was equally studied. The results indicated that suitable time for complete transformation of the most stable carbide phase Cr 3 C 2 was achieved by heating the chromium coated fiber for 6 h in vacuum at 900 °C. has been presented. The progression of surface modification from the basic thermochemical treatment through conversion coating to vapour deposition
The three Schiff bases namely NPNA (L 1 ): N-[(E)-Pheny lmethylene]Naphthalene-1-Amine, newly NNNA (L 2 ): N-[(E)-1-Naphthylmethylene]Naphthalene-1-Amine and NFNA (L 3 ): N-[(E)-2-Furylmethylene] Naphthalene-1-Amine have been synthesized in equimolar reaction of 1-Naphthylamine hydrochloride with or naphthalene-1-carbaldehyde or 2-furfuraldehyde in the presence of acetic acid glacial. The characterization of Schiff bases was done by 1 HNMR, UV–VIS, IR, spectral studies and analytical data. Keywords: Schiff bases, aromatic aldehyde, spectroscopic studies. DOI: 10.7176/CMR/13-3-02 Publication date: October 31 st 2021
Aluminium alloys, and particularly aluminium silicon alloys, have found extensive use in engineering applications.Improving the mechanical properties of the cast alloys is important.One of the means of achieving this is by grain refinement using grain refiners.The grain refiners affect the fluidity, and consequently solidification, of the alloys.In this study, the fluidity of nineteen Al-Si alloys made with silicon of 99.999% purity and aluminum of 99.999% purity were investigated using a straight channels mold.The casting modulus of the channels varied between 0.2 mm and 2.9 mm.Using the same quality of materials, Ti-B-Al was added to alloys with silicon content between 0% and 16%.In the 0.91 mm modulus channel a decrease varying from 50% to 2% was observed in the solid solution alloys while in the hypo-eutectic alloys fluidity decreased by 16% to 45%.However, in the hyper-eutectic alloys, fluidity increased by 8% to 18%.
Sample preparation is one of the crucial steps in any chemical analysis because most samples are not ready to introduce directly into analytical instruments. This step is very important to eliminate interferences, isolate and preconcentration of analytes of interest from the matrix and makes them more suitable for separation and detection. The extraction of analytes from aqueous matrices can be traditional and nontraditional techniques. Miniaturized techniques are simple, solventless or solvent-reduced techniques allowing the extraction and concentration in a single step on a micro scale approach. Stir Bar Sorptive Extraction (SBSE) is a relatively new solventless sample preparation method for the extraction and concentration of organic compounds from aqueous matrices of environmental, food and biological samples. In SBSE, a stir bar coated with Polydimethylsiloxane (PDMS) phase is added to a vial containing the sample. The sample is then stirred until analytes partition equilibrium time reached with sorbent. The extracts can be introduced quantitatively into the analytical system by thermal or liquid desorption. The efficiency of extraction of SBSE in terms of the amount extracted and the equilibrium is affected by extraction time, stirring speed, temperature of the sample, pH, salting and sample volume. The most important limitation of SBSE is the only commercial availability of PDMS coating material exists at present. Besides, due to the non-polar character of PDMS, SBSE technique is mainly applied to extract non-polar and weakly polar compounds but failed in extraction of strongly polar compounds. Keywords : Stir Bar Sorptive Extraction, Polydimethylsiloxane, Sample Preparation, Organic Compounds DOI: 10.7176/CMR/13-1-01 Publication date: January 31 st 2021
Alkaline paper has advantages in their high shelf life (permanence) compared to paper made in acidic conditions. The conversion from acidic papermaking process to alkaline process is a major change experienced by the paper industry. In alkaline papermaking, one of the internal sizing agent used is Alkylketene Dimer (AKD). This additive is used to improve the resistance of paper to liquid penetration. Changes to the use of sizing agents are also followed by other changes; one of them is the change in the retention aids used. The use of Cationic Polyacrylamide (C-PAM) as retention aid on alkaline papermaking which is sized by AKD has been investigated. In this study, 100% Leaf Bleached Kraft Pulp (LBKP) as a fiber source was refined in a laboratory beater up to 400 mLCSF of freeness and then mixed with paper additives i.e. 0.1% AKD as sizing agent, 15% calcium carbonate as filler and 1% cationic starch as dry strength agent. The addition of C-PAM was varied in the range of 0% - 0.4% based on dry weight of fiber. After being mixed thoroughly, the handsheets of 60 g/m2 grammage were made and then tested for tensile strength and water absorption (Cobb-60). The addition of 0.1% C-PAM resulted paper with good tensile strength and improved the resistance to liquid penetration. Keywords: Alkaline paper, AKD sizing, C-PAM, tensile strength, water absorption (Cobb-60) DOI: 10.7176/CMR/12-6-04 Publication date: July 31 st 2020
Nanocrystalline PbS thin films were deposited on glass substrates with various deposition times using chemical bath deposition technique. PbS thin films were prepared by using a solution of Lead nitrate and thiourea by using NaOH salt as a complexing agent and ammonia solution as a pH adjuster at 65 0 C. The study was carried out for thickness in the range of (0.16-1.03m). The structural properties were carried out by X-ray diffraction (XRD). The X-ray diffraction patterns reveal that the films exhibit the cubic face centered structure. The crystalline sizes of the films increased with increasing film thickness. The morphological properties were studied by SEM and showed that films were well adherent to the substrate, uniform, small crystal size and covered the entire substrate surface completely. The optical properties of these films have been studied and show that PbS thin films have the values of energy gap varied between (0.88-1.34 eV) with increasing film thickness. Keywords: CBD, XRD, band gap, PbS thin film DOI: 10.7176/CMR/12-7-01 Publication date: September 30 th 2020
Hydrazones are strong reducing agents. Some hydrazones like hydrazine are is highly toxic and unstable and are therefore found dissolved in water. Chicken dung contains amines and uric acid that are potential sources of hydrazones. This paper reports on the use of chicken dung as an important raw material for the industrial hydrazones. In this study, we investigated the conversion of amine to amide compounds in chicken dung and later chlorine treatment to produce impure hydrazones. In the preparation, 1.0 kg of the chicken dung was soaked in 2.0 litres of distilled water for fifteen days. After filtration, the leachate obtained was treated with chlorine gas. The chemical conversion of the compounds in the chicken dung leachate before and after chlorination was monitored using FT-IR and MS. A sample of pure hydrazine hydrate was analyzed using the two techniques and the spectra obtained was used as a reference standard. The findings of this study indicate that chicken dung is rich in amine-containing compounds that can be converted to amide derivatives under ambient conditions. A comparison of FT-IR and MS data before and after chlorination indicated the formation of hydrazones. The findings of this study provide some scientific rationale for using chicken dung as an alternative source of industrial hydrazones. Keywords: Hydrazones, amines, amides, chicken dung. DOI: 10.7176/CMR/12-7-02 Publication date: September 30 th 2020
Soil contamination by heavy metals is increasing day by day. In this study, pollution indices which include geo-accumulation index (I-geo), enrichment factor (EF), environmental risk factor (ERF), contamination factor (CF), degree of contamination (CD), contamination/pollution index (C/PI) and pollution load index (PLI) among others were used. The City was divided into four zones; Northwest (NW), Northeast (NE), Southwest (SW) and Southeast (SE). The average total levels of heavy metals in soil samples analyzed in SE, SW, NE, NW and control were 143.1, 118.6, 129.1, 143.3 and 0.85 mg/kg respectively. The levels of Cd in soils from all the zones were greater than the target values. The results of the I-geo ranged between highly polluted to very highly polluted. The CF showed very high level of contamination for all the heavy metals in all the zones. The C/PI values were less than 1 (contamination range) for all the heavy metals in all zones except for Cd which was greater than 1 (pollution range) in all zones. The negative values of ERF recorded for all the metals in all zones implied that the heavy metals analyzed may present potential environmental threat. The PLI values were 331.08, 313.12, 287.54 and 313.86 for NW, NE, SW and SE respectively. This study revealed that automobile workshop is one of the major sources of anthropogenic soil pollution in Benin City and its environs. Keywords : Automobile Workshop, Heavy Metals, Pollution Indices and Soil. DOI: 10.7176/CMR/12-4-04 Publication date: April 30 th 2020
The nanocrystals of semiconducting metal oxides have attracted great attention because of their interesting properties. Therefore, our study of some physical properties of the pure and Sb doping Tin Oxide powder , The measurement of the infrared spectrum of pure tin oxide powder shows vibrational frequencies (415.585 - 574.683 - 1641.13 – 2125.3- 3432.67) cm-1 and for Sb doping tin oxide ;(x=0.03) shows vibration frequencies and the most prominent is ( 573.719 – 941.092 – 1384.64 – 1637.27 – 3415.56 ) cm-1 , the study showed that the greatest value of the absorbance and absorption coefficient was in doping sample respectively A = 0.819, α = 18.839 cm-1 corresponding to the wavenumber ʋ = 573.719 cm-1, the greatest value of the optical conductivity was in pure sample 0.0831(Ωcm)-1 corresponding to the wavenumber ʋ = 3432.67 cm-1 and the refractive index for pure tin oxide ranged from [1.832 - 2.371]. As for the Sb doping Tin Oxide powder, the refractive index value was between [1.122 – 2.152 ]. Keywords: Tin Oxide - infrared spectrum - absorbance - absorption coefficient - refractive index - optical conductivity. DOI: 10.7176/CMR/12-6-01 Publication date:July 31st 2020
This work presents an exploration of the use of hydroxysodalite zeolite prepared from basalt rich in calc-plagioclaseby alkali activation for removal of some heavy metals from aqueous medium. The preliminary results of batch and column experiments indicated a quantitative and fast removal of the three investigated ions, Cu 2+ , Pb 2+ and Zn 2+ from aqueous solutions. The data from the batch experiments and the column experiments jointly support the notion that hydroxysodalite zeolite prepared from basalt rich in calc-plagioclase is an efficient adsorbent for the investigated heavy metals. Almost quantitative removal of the ions was achieved within a period of 15 min of exposure of the solution to the adsorbent in batch experiments and through passing a small column filled with the adsorbent. The highest removal efficiency by the zeolite prepared from basalt rich in calc-plagioclase of the three tested heavy metal Cu 2+ , Pb 2+ and Zn 2+ were 99.98% ,99.76% and 99.93 % respectively. Keywords: hydroxysodalite zeolite, basalt utilization, heavy ions removal, pollution remediation DOI: 10.7176/CMR/12-7-09 Publication date: November 30 th 2020
The potentiality of diethylamine as deproteination and deacetylation agent in the extraction of chitosan from Scylla serrata (giant mud crab) shell was investigated. The aim was to find an alternative agent to inorganic alkalis as possible replacement for use in the production of high quality chitosan with the right stability. Pretreatment of the shell was carried out and followed by demineralization using hydrochloric acid. Diethylamine was used for deproteination and deacetylation by modifying some published protocols. Moisture, ash, fat and protein contents of the extracts were determined using their respective standard methods. Fourier Transform Infrared (FTIR) technique was used for spectroscopic analysis. Scylla serrata shell was composed of 14.25% protein, 32.84% mineral (CaCO 3 ), 31.52% chitin and 21.39% chitosan. Moisture, ash, fat and protein contents of chitin extracted from Scylla serrata shell were 2.35%, 3.03%, 1.79% and 3.85% respectively while those of chitosan were 1.65%, 3.84%, 0.53% and 2.80% respectively. Degree of deacetylation (DDA) and carbon to nitrogen ratio were 69.24% and 5.67 respectively. FTIR spectra of the extracted chitin and chitosan from Scylla serrata showed the presence of some active compounds of carbonyl, amide, amine and hydroxyl groups. However, CH 3 waging along chain (952 cm -1 ), CO stretching at 1026 cm -1 and 1073 cm -1 , and amide II band (1563 cm -1 ) were not found in the extracted chitin while HPO 4 2- and amide III were also not found in the extracted chitosan. These moieties were present in the standard chitin and chitosan respectively. This study has shown that diethylamine (organic base) has great potential as agent of deproteination and deacetylation in the extraction of chitosan from Scylla serrata . Consequently, academic activity in the area of investigation of the stability of the extracted chitosan from Scylla serrata using diethylamine as deproteination and deacetylation agent is strongly recommended. Keywords : Diethylamine, deproteination, deacetylation, chitin and chitosan, Scylla serrata shell. DOI: 10.7176/CMR/12-7-07 Publication date: October 31st 2020
Inside a ladle there is one component of the material that often gets damaged, namely the Holding Magnet Type LS50, which has corrosion (damage) on the surface due to temperatures that reaches 1500 °C with a time limit of 150 minutes. Test shows the material contained in the Holding Magnet Type LS50 are steel, copper (CuZn), and magnet. The Steel of Holding Magnet Type LS50 has a chemical composition with the main ingredient of iron (Fe) around 97.961% and other elements such as carbon, silicon, manganese, chromium and other alloy elements. As for the microstructure, CuZn has a microstructure in the form of an α (alpha) phase and a ß (betha) phase. The average of Holding Magnet hardness test results shows only CuZn experienced a very drastic decrease in the hardness value due to continuous heat exposure while the temperature for CuZn melting point is only 1084 ° C. Keywords: Chemical Composition, Metallography, Hardness. DOI: 10.7176/CMR/12-7-08 Publication date: October 31st 2020
Personalized therapy (PM) has the potential to adapt treatment with the best response and highest safety to provide better patient care. Key data is drug concentration of biological materials such as plasma and serum.Individual drug therapy means, choice of a drug and its dose regime should fit every individual specifically. Thus efficacy of a drug treatment would improve significantly. When developing an analytical method for (Therapeutic drug monitoring) TDM, it is important to choose a clinically relevant calibration range. This quantitation range should be built around the proposed target concentration, covering majority of samples as seen in the clinic (Ciocan-Cartita et al. 2019).Inter-individual variability in Pharmacokinetic variables may affect the blood concentration of drug so TDM approaches could solve the dosing problem.To achieve individual drug therapy with a reasonably predictive outcome, one must further account for different patterns of drug response among geographically and ethnically distinct populations. Keywords: LC-MS/MS, Therapeutic Drug Monitoring, Lenalidomide, Anastrozole DOI: 10.7176/CMR/12-7-05 Publication date: September 30 th 2020
