Search results for: commercial activated carbon

Authors: Vara Prasad Vemu

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The aim of the present work is to investigate the mechanical properties and water absorption capacity of carbon and basalt fibers mixed with matrix epoxy. At present, there is demand for nature friendly products. Basalt reinforced composites developed recently, and these mineral amorphous fibres are a valid alternative to carbon fibres for their lower cost and to glass fibres for their strength. The present paper describes briefly on basalt and carbon fibres (uni-directional) which are used as reinforcement materials for composites. The matrix epoxy (LY 556-HY 951) is taken into account to assess its influence on the evaluated parameters. In order to use reinforced composites for structural applications, it is necessary to perform a mechanical characterization. With this aim experiments like tensile strength, flexural strength, hardness and water absorption are performed. Later the mechanical properties obtained from experiments are compared with ANSYS software results.

Keywords: carbon fibre, basalt fibre, uni-directional, reinforcement, mechanical tests, water absorption test, ANSYS

Procedia PDF Downloads 197

Authors: Mohammad Ebrahim Kianifar, Ehsan Ahmadi

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Reinforced concrete structures experience local defects such as cracks over their lifetime under various environmental loadings. Consequently, they are repaired by mortars to avoid detrimental effects such as corrosion of reinforcement, which in long-term may lead to strength loss of a member or collapse of structures. However, repaired structures may need multiple repairs due to changes in load distribution, and thus, lack of compatibility between mortar and substrate concrete. On the other hand, waste tire rubber alkali-activated (WTRAA)-based materials have very high potential to be used as repair mortars because of their ductility and flexibility, which may delay the failure of repair mortar and thus, provide sufficient compatibility. Hence, this work presents a pioneering study on suitability of WTRAA-based materials as mortars for the repair of concrete structures through an experimental program. To this end, WTRAA mortars with 15% aggregate replacement, alkali-activated (AA) mortars, and ordinary mortars are made to repair a number of concrete beams. The WTRAA mortars are composed of slag as base material, sodium hydroxide as an alkaline activator, and different gradations of waste tire rubber (fine and coarse gradations). Flexural tests are conducted on the concrete beams repaired by the ordinary, AA, and WTRAA mortars. It is found that, despite having lower compressive strength and modulus of elasticity, the WTRAA and AA mortars increase the flexural strength of the repaired beams, give compatible failures, and provide sufficient mortar-concrete interface bondings. The ordinary mortars, however, show incompatible failure modes. This study demonstrates the promising application of WTRAA mortars in the practical repairs of concrete structures.

Keywords: alkali-activated mortars, concrete repair, mortar compatibility, flexural strength, waste tire rubber

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Authors: Sultan Haji Shube

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Woodland ecosystems of semiarid rift valley of Ethiopia play a significant role in climate change mitigation by sequestering and storing more carbon. This study was conducted in Gidabo river sub-basins southeastern rift-valley escarpment of Ethiopian. It aims to estimate biomass and carbon stocks of woodlands and its implications for climate change mitigation. A total of 44 sampling plots (900m²each) were systematically laid in the woodland for vegetation and environmental data collection. A composite soil sample was taken from five locations main plot. Both disturbed and undisturbed soil samples were taken at two depths using soil auger and core-ring sampler, respectively. Allometric equation was used to estimate aboveground biomass while root-to-shoot ratio method and Walkley-Black method were used for belowground biomass and SOC, respectively. Result revealed that the totals of the study site was 17.05t/ha, of which 14.21t/ha was belonging for AGB and 2.84t/ha was for BGB. Moreover, 2224.7t/ha total carbon stocks was accumulated with an equivalent carbon dioxide of 8164.65t/ha. This study also revealed that more carbon was accumulated in the soil than the biomass. Both aboveground and belowground carbon stocks were decreased with increase in altitude while SOC stocks were increased. The AGC and BGC stocks were higher in the lower slope classes. SOC stocks were higher in the higher slope classes than in the lower slopes. Higher carbon stock was obtained from woody plants that had a DBH measure of >16cm and situated at plots facing northwest. Overall, study results will add up information about carbon stock potential of the woodland that will serve as a base line scenario for further research, policy makers and land managers.

Keywords: allometric equation, climate change mitigation, soil organic carbon, woodland

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Authors: Jiraporn Burakorn, Pran Pinthong, Supida Hutabaedya

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Commercial traditional pork sausages (Moo Yaw) were produced by added more than 30% of pork fat for appetite customer. The pork sausages texture were softness, firmness, juiciness and smooth. If the pork sausages contained less fat, their textures were hardness, dryness and incoherence. This research investigated production of low fat traditional pork sausage containing transglutaminase for improved its sensory properties and nutritive values. The enzyme pork sausage composed of transglutaminase, soybean cake, rice bran oil and other ingredients. Consumer acceptance test was done by comparing the enzyme pork sausage with the 3 commercial pork sausage with 95 consumer. The enzyme pork sausage was accepted 92.6% and was preferred in all attributes over the 3 commercial pork sausages such as appearance, color, flavor, taste, firmness and overall liking. The enzyme pork sausage was high protein but low total calories, calories from fat, total fat, saturated fat, cholesterol and carbohydrate. The enzyme pork sausage was lower calorie (90 kcal) than the commercial reference pork sausage (150 kcal) 64%. The morphological texture of the enzyme pork sausage was smooth and consistency when analyzed by SEM.

Keywords: low fat, Moo Yaw, pork sausage, transglutaminase

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Authors: Thapelo Jacob Moloi

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This paper purports to present the findings in relation to the competencies of commercial grain farmers using a classic grounded theory method. A total of about eighteen semi-structured interviews with farmers, former farmers, farm workers, and agriculture experts were conducted. Findings explored competencies in the form of skills, knowledge and personal attributes that commercial grain farmers possess. Skills range from production skills, financial management skill, time management skill, human resource management skill, planning skill to mechanical skill. Knowledge ranges from soil preparation, locality, and technology to weather knowledge. The personal attributes that contribute to shaping a commercial grain farmer are so many, but for this study, seven stood out as a passion, work dedication, self-efficacy, humbleness, intelligence, emotional stability, and patience.

Keywords: grain farming, farming competencies, classic grounded theory, competency model

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Authors: S. Habibi, T. E. Guarcia, A. Megueni, A. Ziadi, L. Aminallah, A. S. Bouchikhi

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The characterization of the microstructure of Dual Phase steel in various low-carbon, with a yield stress between 400 and 900 MPa were conducted .In order to assess the mechanical properties of steel, we examined the influence of their chemical compositions interictal and heat treatments (austenite + ferrite area) on their micro structures. In this work, we have taken a number of commercial DP steels, micro structurally characterized and used the conventional tensile testing of these steels for mechanical characterization.

Keywords: characterization, construction in civil engineering, micro structure, tensile DP steel

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Authors: Katerina Bakela, Ioanna Zerva, Irene Athanassakis

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Lipopolysaccharide (LPS) is commonly used in murine sepsis models, which are largely associated with immunosuppression (incretion of MDSCs cells and Tregs, imbalance of inflammatory/anti-inflammatory cytokines) and collapse of the immune system. After adapting the LPS treatment to the needs of locally bred BALB/c mice, the present study explored the protective role of Micrococcus luteus peptidoglycan (PG) pre-activated vaccine-on chip in endotoxemia. The established protocol consisted of five daily intraperitoneal injections of 0.2mg/g LPS. Such protocol allowed longer survival, necessary in the prospect of the therapeutic treatment application. The so-called vaccine-on-chip consists of a 3-dimensional laser micro-texture Si-scaffold loaded with BALB/c mouse macrophages and activated in vitro with 1μg/ml PG, which exert its action upon subcutaneous implantation. The LPS treatment significantly decreased CD4+, CD8+, CD3z+, and CD19+ cells, while increasing myeloid-derived suppressor cells (MDSCs), CD25+, and Foxp3+ cells. These results were accompanied by increased arginase-1 activity in spleen cell lysates and production of IL-6, TNF-a, and IL-18 while acquiring severe sepsis phenotype as defined by the murine sepsis scoring. The in vivo application of PG pre-activated vaccine-on chip significantly decreased the percent of CD11b+, Gr1+, CD25+, Foxp3+ cells, and arginase-1 activity in the spleen of LPS-treated animals, while decreasing IL-6 and TNF-a in the serum, allowing survival to all animals tested and rescuing the severity of sepsis phenotype. In conclusion, these results reveal a promising mode of action of PG pre-activated vaccine-on chip in LPS endotoxemia, strengthening; thus, the use of treatment is septic patients.

Keywords: myeloid-derived suppressor cells, peptidoglycan, sepsis, Si-scaffolds

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Authors: Xuechen Gui, Senmiao Li, Qi Kan

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Dormitory is a place for college students to study and live their daily life. The indoor environment quality of the dormitory is closely related to the physical health, mood status and work efficiency of the dormitory students. In this paper, the temperature, humidity and carbon dioxide concentration of the dormitory in Zijingang campus of Zhejiang University have been tested for three days. The experimental results show that the concentration of carbon dioxide is related to the size of the window opens and the number of dormitory staff, and presents a high concentration of carbon dioxide at nighttime while a low concentration at daytime. In terms of temperature and humidity, there is no significant difference between different orientation and time and presents a small humidity at daytime while a high humidity at nighttime.

Keywords: dormitory, indoor environment, temperature, relative humidity, carbon dioxide concentration

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Authors: Amal Aljohani, Ahmed Iraqi

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Emitting materials with thermally activated delayed fluorescence (TADF) properties as the third generation of organic light-emitting diodes (OLEDs) have received much attention as a modern class of highly efficient emitters because such properties enable the harvesting of both singlet and triplet excitons in EL applications without the doping with complexes of scarce noble metals such as platinum and iridium. Improved molecular design of TADF molecules and applied materials exhibiting internal electroluminescence (EL) with quantum efficiencies of nearly 100% has been achieved being. A2B3 hyperbranched polymers based on new derivatives containing silane core units serving as host materials for thermally activated delayed fluorescence (TADF) guest molecules have been designed and synthesized through several steps, including the synthesis of tetrakis(4-bromophenyl)silane, bis(4-(9H-carbazol-9-yl)phenyl)bis(4-bromophenyl)silane,bis(4-(9H-carbazol-9 yl)phenyl)bis(4-methoxyphenyl)silane and bis(4-(9H-carbazol-9-yl)phenyl)bis(4hydroxyphenyl)silane. This monomer has been used successfully used along with 1,1,1-tri-(p-tosyloxymethyl)-propane to prepare A2B3 hyperbranched polymers via step-growth polymerization. The characterization and the properties of these new host polymers will be presented and discussed in this contribution.

Keywords: carbazole, organic light emitting diodes, thermally activated delayed fluorescence, donor-acceptor, host and guest interaction

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Authors: Lucija Pustahija, Christine Bandl, Wolfgang Kern, Christian Mitterer

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Concerning today´s ecological demands, producing reliable materials from sustainable resources is a continuously developing topic. Such an example is the production of carbon materials via pyrolysis of natural gases or biomass. The amazing properties of pyrolytic carbon are utilized in various fields, where in particular the application in building industry is a promising way towards the utilization of pyrolytic carbon and composites based on pyrolytic carbon. For many applications, surface modification of carbon is an important step in tailoring its properties. Therefore, in this paper, an investigation of different oxidation methods was performed to prepare the carbon surface before functionalizing it with organosilanes, which act as coupling agents for epoxy and polyurethane resins. Made in such a way, a building material based on carbon composites could be used as a lightweight, durable material that can be applied where water or air filtration / purification is needed. In this work, both wet and dry oxidation were investigated. Wet oxidation was first performed in solutions of nitric acid (at 120 °C and 150 °C) followed by oxidation in hydrogen peroxide (80 °C) for 3 and 6 h. Moreover, a hydrothermal method (under oxygen gas) in autoclaves was investigated. Dry oxidation was performed under plasma and corona discharges, using different power values to elaborate optimum conditions. Selected samples were then (in preliminary experiments) subjected to a silanization of the surface with amino and glycidoxy organosilanes. The functionalized surfaces were examined by X-ray photon spectroscopy and Fourier transform infrared spectroscopy spectroscopy, and by scanning electron microscopy. The results of wet and dry oxidation methods indicated that the creation of functionalities was influenced by temperature, the concentration of the reagents (and gases) and the duration of the treatment. Sequential oxidation in aq. HNO₃ and H₂O₂ results in a higher content of oxygen functionalities at lower concentrations of oxidizing agents, when compared to oxidizing the carbon with concentrated nitric acid. Plasma oxidation results in non-permanent functionalization on the carbon surface, by which it´s necessary to find adequate parameters of oxidation treatments that could enable longer stability of functionalities. Results of the functionalization of the carbon surfaces with organosilanes will be presented as well.

Keywords: building materials, dry oxidation, organosilanes, pyrolytic carbon, resins, surface functionalization, wet oxidation

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Authors: M. Fernanda Salgado, Alfonso Tierra, David S. Sandoval, Wilbert G. Aguilar

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Public transportation buses usually vary the speed depending on the places with the number of passengers. They require having efficient travel planning, a plan that will help them choose the fast route. Initially, an estimation tool is necessary to determine the travel time of each route, clearly establishing the possibilities. In this work, we give a practical solution that makes use of a concept that defines as areas of commercial incidence. These areas are based on the hypothesis that in the commercial places there is a greater flow of people and therefore the buses remain more time in the stops. The areas have one or more segments of routes, which have an incidence factor that allows to estimate the times. In addition, initial results are presented that verify the hypotheses and that promise adequately the travel times. In a future work, we take this approach to make an efficient travel planning system.

Keywords: commercial incidence, planning, public transport, speed travel, travel time

Procedia PDF Downloads 252

Authors: M. Kouhirostamkolaei, M. Kouhirostami, M. Sam, J. Woo, A. T. Asutosh, J. Li, C. Kibert

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Construction is one of the most energy consumed activities in the urban environment that results in a significant amount of greenhouse gas emissions around the world. Thus, the impact of the construction industry on global warming is undeniable. Thus, reducing building energy consumption and mitigating carbon production can slow the rate of global warming. The purpose of this study is to determine the amount of energy consumption and carbon dioxide production during the operation phase and the impact of using new shells on energy saving and carbon footprint. Therefore, a residential building with a re-enforced concrete structure is selected in Babolsar, Iran. DesignBuilder software has been used for one year of building operation to calculate the amount of carbon dioxide production and energy consumption in the operation phase of the building. The primary results show the building use 61750 kWh of energy each year. Computer simulation analyzes the effect of changing building shells -using XPS polystyrene and new electrochromic windows- as well as changing the type of lighting on energy consumption reduction and subsequent carbon dioxide production. The results show that the amount of energy and carbon production during building operation has been reduced by approximately 70% by applying the proposed changes. The changes reduce CO₂e to 11345 kg CO₂/yr. The result of this study helps designers and engineers to consider material selection’s process as one of the most important stages of design for improving energy performance of buildings.

Keywords: construction materials, green construction, energy simulation, carbon footprint, energy saving, concrete structure, designbuilder

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Authors: H. M. Takematsu, B. R. De Camargo, E. F. Noronha

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The use of hydrolyzing enzymes for degradation of lignocellulosic biomass is of great concern for the production of second generation ethanol. Although many hollocelulases have already been described in the literature, much more has to be discovered. Therefore, the aim of this study to evaluate hollocelulase production of P. polonicum grown in liquid media containing sugarcane bagasse as the carbon source. From a collection of twenty fungi isolated from Cerrado biome soil, P. polonicum was molecular identified by sequencing of ITS4, βtubulin and Calmodulin genes, and has been chosen to be further investigated regarding its potential production of hydrolyzing enzymes. Spore suspension (1x10-6 ml-1) solution was inoculated in sterilized minimal liquid medium containing 0,5%(w/v) of non-pretreated sugarcane bagasse as the carbon source, and incubated in shaker incubator at 28°C and 120 rpm. The supernatant obtained, was subjected to enzymatic assays to analyze xylanase, mannanase, pectinase and endoglucanase activities. Xylanase activity showed better results (67,36 UI/mg). Xylanases bands were indicated by zymogram and SDS-PAGE, and one of them was partially purified and characterized. It showed maximum activity at 50 °C, was thermostable for 72h at 40°C, and pH5.0 was the optimum observed. This study presents P. polonicum as an interesting source of hollocelulases, especially xylanase, for lignocellulose bio-conversion processes with commercial use.

Keywords: sugarcane bagasse, Cerrado biome , hollocelulase, lignocellulosic biomass

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Authors: Shahla Hajializadeh, Maryam Hamedanlou

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Multiwall carbon nanotubes were chemically modified with amide groups for the purpose of enhancing their chemical affinity with waterborne polyurethane. In this study, a thermoplastic nanocomposite containing functionalized multiwall carbon nanotube/waterborne polyurethane (WBPU/MWNT) via in situ polymerization has been prepared. The impacts of MWNT addition on the morphology and electrical properties of nanocomposites were investigated. Micrographs of Scanning Electron Microscopy (SEM) prove that functionalized CNT can be effectively dispersed in WBPU matrix. The electrical conductivity of nanocomposites increased with the CNT contents in as such the nanocomposites containing 1 wt% of MWNT exhibited a conductivity nearly five orders of magnitude higher than the WBPU film.

Keywords: chemical functionalization, electrical properties, in situ polymerization, morphology, multiwall carbon nanotubes, waterborne polyurethane

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Authors: Shamima Akhter, Samira Bagheri, M. Shalauddin, Wan Jefrey Basirun

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In the present study, a nanocomposite of f-MWCNTs-Chitosan was prepared by the immobilization of Co(II) transition metal through self-assembly method and used for the simultaneous voltammetric determination of paracetamol (PA). The composite material was characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-Ray analysis (EDX). The electroactivity of cobalt immobilized f-MWCNTs with excellent adsorptive polymer chitosan was assessed during the electro-oxidation of paracetamol. The resulting GCE modified f-MWCNTs/CTS-Co showed electrocatalytic activity towards the oxidation of PA. The electrochemical performances were investigated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) methods. Under favorable experimental conditions, differential pulse voltammetry showed a linear dynamic range for paracetamol solution in the range of 0.1 to 400µmol L⁻¹ with a detection limit of 0.01 µmol L⁻¹. The proposed sensor exhibited significant selectivity for the paracetamol detection. The proposed method was successfully applied for the determination of paracetamol in commercial tablets and human serum sample.

Keywords: nanomaterials, paracetamol, electrochemical technique, multi-wall carbon nanotube

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Authors: M. A. Karakassides, M. Baikousi, A. Kouloumpis, D. Gournis

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Nanocomposites of Carbon Nanorods (CNRs) with Polystyrene (PS), have been synthesized successfully by means of in situ polymerization process and characterized. Firstly, carbon nanorods with graphitic structure were prepared by the standard synthetic procedure of CMK-3 using MCM-41 as template, instead of SBA-15, and sucrose as carbon source. In order to create an organophilic surface on CNRs, two parts of modification were realized: surface chemical oxidation (CNRs-ox) according to the Staudenmaier’s method and the attachment of octadecylamine molecules on the functional groups of CNRs-ox (CNRs-ODA The nanocomposite materials of polystyrene with CNRs-ODA, were prepared by a solution-precipitation method at three nanoadditive to polymer loadings (1, 3 and 5 wt. %). The as derived nanocomposites were studied with a combination of characterization and analytical techniques. Especially, Fourier-transform infrared (FT-IR) and Raman spectroscopies were used for the chemical and structural characterization of the pristine materials and the derived nanocomposites while the morphology of nanocomposites and the dispersion of the carbon nanorods were analyzed by atomic force and scanning electron microscopy techniques. Tensile testing and thermogravimetric analysis (TGA) along with differential scanning calorimetry (DSC) were also used to examine the mechanical properties and thermal stability -glass transition temperature of PS after the incorporation of CNRs-ODA nanorods. The results showed that the thermal and mechanical properties of the PS/ CNRs-ODA nanocomposites gradually improved with increasing of CNRs-ODA loading.

Keywords: nanocomposites, polystyrene, carbon, nanorods

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Authors: Francia Martinez

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This study documents and demonstrates the profound impact of the high status of American English and culture in Colombian commercial landscape due to the globalization and commodification of English. It also documents and describes how Colombian advertisers make use of various language and visual mechanisms in the commercial linguistic landscape to convey messages, create an image with which the target audience can identify, and build a relationship with that target audience. The data (in the form of pictures) were collected in different cities in Colombia and were classified and organized into different categories for the reliability and validity of the analysis. The research questions were: do the ubiquity and high status of American English and culture play a major role in the Colombian commercial linguistic landscape? If so, how?, what roles do national and local culture and language (Spanish) play in the commercial linguistic landscape?, and what different linguistic and visual strategies do Colombian advertisers employ to reach their target audience? Based on data analysis and results, American and local culture and icons play a major role when Colombian advertisers create and design their commercial logos and ads to get consumers’ attention and establish a rapport with them in a successful way. In order to achieve their objectives, Colombian advertisers rely on creative linguistic and visual techniques in their ads, such as puns, humor, irony, comparisons, metaphors, mocking, exaggeration, parody, personification, sarcasm, satire, allusion, onomatopoeias, and imitation (copycat or cloning).

Keywords: Colombian ads, linguistic landscape, rhetorical devices, sociolinguistics

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Authors: R. Begum, M. M. R. Jahangir, M. Jahiruddin, M. R. Islam, M. M. Rahman, M. B. Hossain, P. Hossain

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Quantifying carbon (C) sequestration in soils is necessary to help better understand the effect of agricultural practices on the C cycle. The estimated contribution of agricultural carbon dioxide (CO₂) and methane (CH₄) to global warming potential (GWP) has a wide range. The underlying causes of this huge uncertainty are the difficulties to predict the regional CO₂ and CH₄ loss due to the lack of experimental evidence on CO₂ and CH₄ emissions and associated drivers. The CH₄ and CO₂ emissions were measured in irrigated wheat in subtropical floodplain soils which have been under two soil disturbance levels (strip vs. conventional tillage; ST vs. CT being both with 30% residue retention) and three N fertilizer rates (60, 100, and 140% of the recommended N fertilizer dose, RD) in annual wheat (Triticum aestivum)-mungbean (Vigna radiata)-rice (Oryza sativa L) for seven consecutive years. The highest CH₄ and CO₂ emission peak was observed on day 3 after urea application in both tillages except CO₂ flux in CT. Nitrogen fertilizer application rate significantly influenced mean and cumulative CH₄ and CO₂ fluxes. The CH₄ and CO₂ fluxes decreased in an optimum dose of N fertilizer except for ST for CH₄. The CO₂ emission significantly showed higher emission at minimum (60% of RD) fertilizer application at both tillages. Soil microbial biomass carbon (MBC), organic carbon (SOC), Particulate organic carbon (POC), permanganate oxidisable carbon (POXC), basal respiration (BR) were significantly higher in ST which were negative and significantly correlated with CO₂. However, POC and POXC were positively and significantly correlated with CH₄ emission.

Keywords: carbon dioxide emissions, methane emission, nitrogen rate, tillage

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Authors: B. Palanikumaran, N. Kanagaraj, M. Sangareswari, V. Sailaja, Kapil Sihag

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The present study aimed to estimate the carbon sequestration potential of major forest types present in the foothills of Nilgiri biosphere reserve. The total biomass carbon stock was estimated in tropical thorn forest, tropical dry deciduous forest and tropical moist deciduous forest as 14.61 t C ha⁻¹ 75.16 t C ha⁻¹ and 187.52 t C ha⁻¹ respectively. The density and basal area were estimated in tropical thorn forest, tropical dry deciduous forest, tropical moist deciduous forest as 173 stems ha⁻¹, 349 stems ha⁻¹, 391 stems ha⁻¹ and 6.21 m² ha⁻¹, 31.09 m² ha⁻¹, 67.34 m² ha⁻¹ respectively. The soil carbon stock of different forest ecosystems was estimated, and the results revealed that tropical moist deciduous forest (71.74 t C ha⁻¹) accounted for more soil carbon stock when compared to tropical dry deciduous forest (31.80 t C ha⁻¹) and tropical thorn forest (3.99 t C ha⁻¹). The tropical moist deciduous forest has the maximum annual leaf litter which was 12.77 t ha⁻¹ year⁻¹ followed by 6.44 t ha⁻¹ year⁻¹ litter fall of tropical dry deciduous forest. The tropical thorn forest accounted for 3.42 t ha⁻¹ yr⁻¹ leaf litter production. The leaf litter carbon stock of tropical thorn forest, tropical dry deciduous forest and tropical moist deciduous forest found to be 1.02 t C ha⁻¹ yr⁻¹ 2.28 t⁻¹ C ha⁻¹ yr⁻¹ and 5.42 t C ha⁻¹ yr⁻¹ respectively. The results explained that decomposition percent at the soil surface in the following order.tropical dry deciduous forest (77.66 percent) > tropical thorn forest (69.49 percent) > tropical moist deciduous forest (63.17 percent). Decomposition percent at soil subsurface was studied, and the highest decomposition percent was observed in tropical dry deciduous forest (80.52 percent) followed by tropical moist deciduous forest (77.65 percent) and tropical thorn forest (72.10 percent). The decomposition percent was higher at soil subsurface. Among the three forest type, tropical moist deciduous forest accounted for the highest bacterial (59.67 x 105cfu’s g⁻¹ soil), actinomycetes (74.87 x 104cfu’s g⁻¹ soil) and fungal (112.60 x10³cfu’s g⁻¹ soil) population. The overall observation of the study helps to conclude that, the tropical moist deciduous forest has the potential of storing higher carbon content as biomass with the value of 264.68 t C ha⁻¹ and microbial populations.

Keywords: basal area, carbon sequestration, carbon stock, Nilgiri biosphere reserve

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Authors: C. F. Popoola, K. Akinsanya, S. B. Babarinde, D. A. Farinde

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This study investigated published financial statement as correlate of investment decision among commercial bank stakeholders in Nigeria. A correlation research design was used in the study. 180 users of published financial statement were purposively sampled from Lagos and Ibadan. Data generated were analyzed using Pearson correlation and regression. The findings of the study revealed that, balance sheet is negatively related with investment decision (r=-.483; p < .01) while income statement (r= .249; p < .001), notes on the account (r= .230; p < .001), cash flow statement (r= .202; p < .001), value added statement (r= .328; p < .001) and five-year financial summary (r= .191 ;p < .01) are positively related with investment decision. Findings also revealed that components of published financial statement significantly predicted good investment decision (R2= .983; F(5,175)=284.5; p < .05) for commercial bank stakeholders. Therefore, it was suggested that Nigeria banks and professional bodies should instigate programs that will increase the knowledge of stakeholders on published financial statement.

Keywords: commercial banks, financial statement, income statement, investment decision, stakeholders

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Authors: Alireza Mohadesi, Ashraf Salmanipour

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A chemically modified glassy carbon electrode for electrocatalytic determination of sulfide was developed using multiwalled carbon nanotubes (MWCNTs) covalently immobilized with 2,6-dichlorophenolindophenol (DPIP). The immobilization of 2,6-dichlorophenolindophenol with MWCNTs was performed with a new synthetic strategy and characterized by UV–visible absorption spectroscopy, Fourier transform infrared spectroscopy and cyclic voltammetry. The cyclic voltammetric response of DPIP grafted onto MWCNTs indicated that it promotes the low potential, sensitive and stable determination of sulfide. The dependence of response currents on the concentration of sulfide was examined and was linear in the range of 10 - 1100 µM. The detection limit of sulfide was 5 µM and RSD for 100 and 500 µM sulfides were 1.8 and 1.3 %. Many interfering species had little or no effect on the determination of sulfide. The procedure was applied to determination of sulfide in waters samples.

Keywords: functionalized carbon nanotubes, sulfide, biological samples, 2, 6-dichlorophenolindophenol

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Authors: Hari Krishna Ayyappa, Reenu Singh

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Rising population and restricted land for development has led towards the growth of vertical buildings and small complexes. It provides many possibilities to change the shape and size of internal space in addition to the social impacts on the commercial spaces. With the increased volatility of necessities of people, the need for mental and physical comfort has continuously increased. . Living in a small space musts minimalist and space- saving cabinetwork results to sustain mortal good. This paper attempts to explore the Influence of Using Minimalist Furniture on the Efficiency of the commercial Space interiors by means of the variable resulting from preceding studies based on literature. A literature review was conducted on research articles to understand the contributing variables in a well designed small commercial spaces. A questionnaire survey was conducted to understand the layout of small commercial spaces with respect to Environmental impact, material, Design elements, Modern approach, Layered lightings, and colours. The problem of small spaces can be resolved by some ways; it's still needed for cabinetwork to develop to be more innovative to accommodate small living spaces. Since cabinetwork is a necessity and not luxury, everybody is in need of it. The spatial factors affecting overall satisfaction at a detailed position were bandied. The variable helped in proposing design ideation and mock ups to explore improved interiors. This paper concludes that most of the principles of the minimalist approach have been overlooked at, which had an impact on the space efficiency in commercial spaces like storage rooms, office area, retail stores, restaurants, and other spaces where business is conducted.

Keywords: materials, modern approach, space efficiency, tall commercial buildings

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Authors: Shuwen Wu, Zhi LI

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Atomically dispersed Fe‒N₄ catalysts are proven as promising alternatives to commercial Pt/C for the oxygen reduction reaction. Most reported Fe‒N₄ catalysts suffer from inferior O‒O bond-breaking capability due to superoxo-like O₂ adsorption, though the isolated dual-atomic metal sites strategy is extensively adopted. Atomic Fe clusters hold greater promise for promoting O‒O bond cleavage by forming peroxo-like O₂ adsorption. However, the excessively strong binding strength between Fe clusters and oxygenated intermediates sacrifices the activity. Here, we first report a Fex/Cu‒N@CF catalyst with atomic Fe clusters functionalized by adjacent single Cu‒N₄ sites anchoring on a porous carbon nanofiber membrane. The theoretical calculation indicates that the single Cu‒N₄ sites can modulate the electronic configuration of Fe clusters to reduce O₂* protonation reaction free energy, which ultimately enhances the electrocatalytic performance. Particularly, the Cu‒N₄ sites can increase the overlaps between the d orbitals of Fe and p orbitals of O to accelerate O‒O cleavage in OOH*. As a result, this unique atomic catalyst exhibits a half potential (E1/2) of 0.944 V in an alkaline medium exceeding that of commercial Pt/C, whereas acidic performance E1/2 = 0.815 V is comparable to Pt/C. This work shows the great potential of single atoms for improvements in atomic cluster catalysts.

Keywords: Hierarchical porous fibers, atomic Fe clusters, Cu single atoms, oxygen reduction reaction; O-O bond cleavage

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Authors: Elham Shakerian, Reza Afarin

Abstract:

The hepatic disease causes approximately 2 million deaths/year worldwide. Liver fibrosis is the last stage of numerous chronic liver diseases, and until now there is no definite cure or drug for it. Activation of hepatic stellate cells (HSCs) is the main reason for fibrosis. Transforming growth factor (TGF-β), as a main profibrogenic cytokine, if increased in these cells, leads to liver fibrosis through smad3 signaling pathways and increasing the expressions of Collagen type I and III, and actin-alpha smooth muscle (αSMA) genes. Curcumin (CUR) is a polyphenolic compound and an active ingredient derived from the rhizome of the turmeric plant that exerts effective antioxidant, anti-inflammatory, and antimicrobial activity. It has been shown that daily consumption of curcumin may have a protective effect on the liver against oxidative stress associated with alcohol consumption. In this study, we investigate the role of Curcumin in decreasing HSC activation and treating liver fibrosis. First, the human HSCs were treated with 2 ng/ml of (TGF-β) for 24 hours to become activated, then with Silibinin for 24 hours. Total RNAs were extracted, reversely transcribed into cDNA, Quantitative Real-time PCR, and western blot were performed. The mRNA expression levels of Collagen type I and III, αSMA genes, and the level of smad3 phosphorylation in TGF-β activated human HSCs treated with Curcumin were significantly reduced compared to human HSCs untreated with Curcumin. Curcumin is effective in reducing the expression of fibrogenic genes in the activated human HSCs treated with TGFB through downregulation of the TGF-β/smad3 signaling pathway. Therefore, Curcumin possesses significant antifibrotic properties in hepatic fibrosis

Keywords: hepatic fibrosis, human HSCs, curcumin, fibrogenic genes

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Authors: V. Revathi, J. Thaarrini, M. Venkob Rao

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This paper presents a study on use of alkali activated bottom ash (BA) and ground granulated blast furnace slag (GGBS) blend in paver blocks. A preliminary effort on alkali-activated bottom ash, blast furnace slag based geopolymer (BA-GGBS-GP) mortar with river sand was carried out to identify the suitable mix for paver block. Several mixes were proposed based on the combination of BA-GGBS. The percentage ratio of BA:GGBS was selected as 100:0, 75:25, 50:50, 25:75 and 0:100 for the source material. Sodium based alkaline activators were used for activation. The molarity of NaOH was considered as 8M. The molar ratio of SiO2 to Na2O was varied from 1 to 4. Two curing mode such as ambient and steam curing 60°C for 24 hours were selected. The properties of paver block such as compressive strength split tensile strength, flexural strength and water absorption were evaluated as per IS15658:2006. Based on the preliminary study on BA-GGBS-GP mortar, the combinations of 25% BA with 75% GGBS mix for M30 and 75% BA with 25% GGBS mix for M35 grade were identified for paver block. Test results shows that the combination of BA-GGBS geopolymer paver blocks attained remarkable compressive strength under steam curing as well as in ambient mode at 3 days. It is noteworthy to know BA-GGBS-GP has promising future in the construction industry.

Keywords: bottom ash, GGBS, alkali activation, paver block

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Authors: Ramin Khamedi, Isa Ahmadi

Abstract:

In this study acoustic emission (AE) signals obtained during deformation and fracture of two types of ferrite-martensite dual phase steels (DPS) specimens have been analyzed in frequency domain. For this reason two low carbon steels with various amounts of carbon were chosen, and intercritically heat treated. In the introduced method, identifying the mechanisms of failure in the various phases of DPS is done. For this aim, AE monitoring has been used during tensile test of several DPS with various volume fraction of the martensite (VM) and attempted to relate the AE signals and failure mechanisms in these steels. Different signals, which referred to 2-3 micro-mechanisms of failure due to amount of carbon and also VM have been seen. By Fast Fourier Transformation (FFT) of signals in distinct locations, an excellent relationship between peak frequencies in these areas and micro-mechanisms of failure were seen. The results were verified by microscopic observations (SEM).

Keywords: acoustic emission, dual phase steels, deformation, failure, fracture

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Authors: T. P. Oladele, C. A. Snyders, S. M. Bradshaw, G. Akdogan

Abstract:

The effect of temperature, contact time and agitation during pre-treatment was investigated on the elution of gold from granular activated carbon at fixed caustic-cyanide concentration and elution conditions. It was shown that there are interactions between parameters during pre-treatment. At 80oC, recovery is independent of the contact time while the maximum recovery is obtained in the absence of agitation (0rpm). Increase in agitation speed from 0 rev/min to 1200 rev/min showed a decrease in recovery of approximately 20 percent at 80°C. Recovery with increased time from 15 minutes to 45 minutes is only pronounced at 25°C with approximately 4 percent increase at all agitation speeds. The results from elution recovery are aimed to give insight into the mechanisms of pre-treatment under the combinations of the chosen parameters.

Keywords: gold, temperature, contact time, agitation speed, recovery

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Authors: Fabrizio Codella, Chris Parker, Samer Saab

Abstract:

The Kigali Amendment is driving the adoption of low Global Warming Potential refrigerants in commercial refrigeration systems in over a hundred countries. Several refrigeration systems for the small and large retail stores at mild and hot ambient temperature climates have been compared for hydrofluorocarbons (HFC), hydrofluoroolefins (HFO), transcritical CO₂ and propane, in typical and advanced system architectures. The results of system performance, emissions and lifetime cost have been compared. The greatest benefits were found to be obtained by low global warming potential HFO advanced systems.

Keywords: commercial refrigeration, CO₂, emissions, HFO, lifetime cost, performance

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Authors: Rafiu Babatunde Ibrahim, Richard Oluseyi Taiwo, Abiodun Toheeb Akintunde

Abstract:

The relationship between road transport infrastructure and commercial activities in Nigeria has been a topical issue and identified as one of the crucial components for economic development in the country. This study examines road transport infrastructure and commercial activities along selected roads in Ede, Nigeria. The study assesses the characteristics of the selected roads, the condition of road infrastructure, the degree of road network connectivity, maintenance culture for the road infrastructure as well as commercial activities along identified roads in the study area. Stratified Sampling Techniques were used to partition the study area into core, Intermediate and Suburb Township zones. Roads were also classified into Major, Distributor and Access Roads. Field observation and measurement, as well as a questionnaire, were used to obtain primary data from 246 systematically sampled respondents along the roads selected, and they were analyzed using descriptive and inferential statistics. The study revealed that most of the roads were characterized by an incidence of potholes. A total of 448 potholes were observed, where Olowoibida Road accounted for (19.0%), Federal Polytechnic Road (17.4%), and Back to Land Road (16.3%). The majority of the selected roads have no street lights and are of open drainage systems. Also, the condition of road surfaces was observed to be deteriorating. Road network connectivity of the study area was found to be poorly connected with 11% using the alpha index and 40% of Gamma index. It was found that the tailoring business (39) is predominant on major roads and Distributor Roads, while petty trading (35) is dominant on the access road. Results of correlation analysis (r = 0.242) show that there is a low positive correlation between road infrastructure and commercial activities; the significant relationships have indeed explained how important it is in influencing commercial activities across the study area. The study concluded by emphasizing the need for the provision of more roads and proper maintenance of the existing ones. This will no doubt improve the commercial activities along the roads in the study area.

Keywords: road transport, infrastructure, commercial activities, maintenance culture

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Authors: Tadele Tesfay Teame, Tsegaye Abrehame, Hágen István Zsombor

Abstract:

Liquidity is one of the main concerns for banks, and thus achieving the optimum level of liquidity is critical. The main objective of this study is to discover the driving force of selected private commercial banks’ liquidity. In order to achieve the objective explanatory research design and quantitative research approach were used. Data has been collected from a secondary source of the sampled Ethiopian private commercial banks’ financial statements, the National Bank of Ethiopia, and the Minister of Finance, the sample covering the period from 2011 to 2022. Bank-specific and macroeconomic variables were analyzed by using the balanced panel fixed effect regression model. Bank’s liquidity ratio is measured by the total liquid asset to total deposits. The findings of the study revealed that bank size, capital adequacy, loan growth rate, and non-performing loan had a statistically significant impact on private commercial banks’ liquidity, and annual inflation rate and interest rate margin had a statistically significant impact on the liquidity of Ethiopian private commercial banks measured by L1 (bank liquidity). Thus, banks in Ethiopia should not only be concerned about internal structures and policies/procedures, but they must consider both the internal environment and the macroeconomic environment together in developing their strategies to efficiently manage their liquidity position and private commercial banks to maintain their financial proficiency shall have bank liquidity management policy by assimilating both bank-specific and macro-economic variables.

Keywords: liquidity, Ethiopian private commercial banks, liquidity ratio, panel data regression analysis

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