Performance characterization of long-distance digital microwave radio systems

Imperial Users onl

Load - Deflection Characteristics of Reinforced Concrete and Reinforced Latecrete Beams at Mid-Span

A laboratory Investigation of the Flexural Strength of Latecrete materials was carried out. The laterite used falls under AASHTO soil classification A-7-6 (10) with low plasticity clay (CL) according to the Unified soil classification system. This laterite is within zone four gradation characterized by fine laterite and has kaolinite as its dominant clay mineral. The Experimental programme involves the fabrication of twenty beams of concrete and latecrete materials; and testing them for flexural strength. Tests show that The Flexural strength recorded for plain concrete beams was 2.89 N/mm2, while plain latecrete beams has a value 1.44 N/mm2. The flexural strength of 13.58 N/mm2 was recorded for the reinforced concrete beams and 7.80 N/mm2 for reinforced latecrete beams, indicating that the flexural strength of latecrete beam is approximately 50% of that of concrete beam specimens. The load-deflection behaviors of the beams are essentially linear within the elastic range of loading. Based on the findings of this investigation, it was observed that the behavior of latecrete is similar to that of concrete; however, the concrete materials showed better strength characteristics than the latecrete materials. Keywords: Concrete, Latecrete, sand, Reinforcement and flexural strength

Modelling the Permeation Properties of Self-Compacting Concrete Incorporating Sporocarcina Pasteuri

The face of concreting has been revolutionized with the development of self-compacting concrete, the introduction of Microbial Induced Calcite Precipitation (MICP) in concrete as well as the use of secondary cementitious materials in concrete, as it helps to improve the pore characterization of the concrete by the filling of the pore spaces and hence enhance its porosity and durability. The use of these revolutionary concrete however requires the optimization of the constituents and/or additives to concrete in order to maximize the properties thereof. There is thus a need to arrive at optimal materials quantities that can maximize the porosity characterization of the concrete without recourse to many trial and error experimentations that are both time and resources consuming. The application of modelling tools in concrete technology aids in the optimization of concrete constituents for optimal self-compacting concrete performance. In this research linear optimization models for predicting the water absorption and sorptivity of the Bio- self-compacting concrete incorporating sporosarina Pasteurii at different bacterial cell density and nutrient content with respect to age of concrete were developed for these concrete properties at 7 and 28 days with the bacterial concentration and calcium calcite content as the independent variables and water absorption and sorptivity as dependent variables; and the developed models validated using experimental data in DataFit Software. Results obtained showed that the developed linear models which took the quadratic form y(x)=a_1+a_2 x+a_3 x^2+⋯+a_n x^(n-1) were adequate for the prediction and optimization of the water absorption and sorptivity of the bio- self-compacting concrete.JCEM

Effects of Sesame Straw Ash as a Substitute for Cement on Strength Characteristics of Concrete

Concrete is broadly used as a building material across the globe, and its use is raising the need of cement in the construction industries. High price of cement and environmental debasement are the driving problems forcing the researchers to come up with alternative materials from large volumes of agricultural wastes as a partial replacement for cement. This study aims at recycling agricultural waste ash (i.e.  Sesame straw ash) as a substitute for cement in the production of sustainable and environmentally friendly greener concrete. Preliminary tests on constituent materials were conducted in order to find out their physical properties. Influences of sesame straw ash (SSA) on cement paste were looked into for addition of 0, 5, 10, 15, 20 and 25 % by weight of cement. The Compressive and flexural strengths as well as the slump of concrete made with different portions of SSA (i.e. 0 – 25 %) were investigated. A 100 mm cubes and 100 mm X 100 mm X 450 mm beams of SSA-concrete were tested for compressive and flexural strengths at 3, 7, 28, 56 and 90 days of curing in line with procedure outlined in BS 1881-116: (1983) and BS 1881-118: (1983) respectively. The outcomes of the workability test show that as the portion of SSA increases the workability a fresh concrete decreases, but consistency, setting times, and soundness of SSA-cement paste increase as the portion of SSA increases. However, the strengths of SSA-concrete increase as the duration of curing increases, and decrease as the portion of SSA increases. It was detected that the strength of concrete produced with 10 % SSA content was beyond the designed strength of 20 N/mm2 at 28 days of curing. In addition, the densities of SSA-concrete samples fall within the limits of 2200 kg/m3 to 2600 kg/m3. Finally, it was concluded that the maximum amount of SSA to be used should not exceed 10 % replacement in concrete production

Effects of the Partial Replacement of Cement with Cassava Peel Ash and Rice Husk Ash on Concrete

Being the third-largest emitter of greenhouse gases (GHG) globally, the cement industry has come under scrutiny by the international community lately. In a bid to remedy the situation, researchers worldwide are keen on finding alternative materials to partially or fully replace Portland cement in concrete production. Materials such as industrial waste, biological waste, agricultural and domestic waste have been used. In this study, a ternary blend of Ordinary Portland Cement, Cassava Peel Ash (CPA), and Rice Husk Ash (RHA) were introduced as the binder System in concrete production to reduce the use of Portland cement. The concrete mix was prepared to put CPA at 5% for all combinations while the RHA was varied from 0 to 25% of the total binder content. With a 0.65 water/binder ratio, an optimum strength was reached at 20% replacement of CPA (5%) and RHA (15%). The partial replacement of cement with CPA – RHA in concrete has also positively affected concrete's water absorption properties. From the use of these materials, GHG emissions are reduced, and the waste generated from the pile of cassava peel and rice husk is eliminated

Effects of the Partial Replacement of Cement with Cassava Peel Ash and Rice Husk Ash on Concrete

Being the third-largest emitter of greenhouse gases (GHG) globally, the cement industry has come under scrutiny by the international community lately. In a bid to remedy the situation, researchers worldwide are keen on finding alternative materials to partially or fully replace Portland cement in concrete production. Materials such as industrial waste, biological waste, agricultural and domestic waste have been used. In this study, a ternary blend of Ordinary Portland Cement, Cassava Peel Ash (CPA), and Rice Husk Ash (RHA) were introduced as the binder System in concrete production to reduce the use of Portland cement. The concrete mix was prepared to put CPA at 5% for all combinations while the RHA was varied from 0 to 25% of the total binder content. With a 0.65 water/binder ratio, an optimum strength was reached at 20% replacement of CPA (5%) and RHA (15%). The partial replacement of cement with CPA – RHA in concrete has also positively affected concrete's water absorption properties. From the use of these materials, GHG emissions are reduced, and the waste generated from the pile of cassava peel and rice husk is eliminated

An Investigation into the Thermal Performance of Rubber-Concrete

The Thermal properties of concrete incorporating pulverized automobile tires as partial replacement for mineral coarse aggregate (granite) was investigated in other to assess its suitability as a construction material and also a solution to the environmental problems constituted by non-biodegradable waste tires. Replacement was made at: 5%, 10%, 15%, 20% and 25% by volume. Thermal properties were measured base on the transient line heat source (TLS) method using a KD 2 Pro thermal analyzer. Thermal properties most especially the thermal conductivity of concrete (1.816W/mk) have been greatly reduced to 1.283W/mk indicating 29.4% reduction after 25% partial replacement of mineral aggregate with the rubber particles which makes it a better insulator while the specific heat capacity of concrete (3.040 MJ/m3.k) have been reduced to 2.137MJ/m3k indicating 29.7% reduction with same 25% rubber particles which may adversely reduce thermal mass effect. Other thermal properties such as thermal resistivity increased by 29.4%, thermal diffusivity decreases by 65.1% while thermal effusivity decreases by 37.6% with 25% rubber particles content in concrete. The result indicates that the potential use of such composite material for building applications is viable. DOI: 10.5901/ajis.2014.v3n5p2

In silico screening of potential Tumor necrosis factor alpha (TNF-α) inhibitors through molecular modeling, molecular docking, and pharmacokinetics evaluations

The multifunctional cytokine TNF-α serves as a key biological mediator for several important immune processes, such as inflammation, infection, and antitumor responses. It is crucial for both acute and chronic neuroinflammation, as well as several neurodegenerative diseases. For the treatment of inflammatory diseases, the synthetic antibodies etanercept, adalimumab, and the generic medication Diclophenac directly bind to TNF-α, preventing it from interacting with the tumor necrosis factor receptor (TNFR). These approved drugs have detrimental side effects. There is therefore a lot of interest in the scientific world to identify new small-molecule-based TNF-α inhibition therapies. In this study, a set of molecular modeling techniques have been applied including the QSAR model, docking, and pharmacokinetics prediction to identify and optimize novel TNF-α inhibitors. Based on the modeling techniques applied, the QSAR shows (R2= 0.9534, Q2 = 0.8707, Rpred2= 0.8599, cRr2= 0.8994, SEE = 0.1067). The results showed that the function of these discovered compounds was not connected to lipophilicity, whereas less lengthy NN bonds and long substituents might lead to quite bioactive molecules. The discovered hits indicate promising inhibition against TNF-α and lacked harmful effects. Most of the discovered molecules had higher TNF-binding affinity than the reference substance. Furthermore, comparing the reference drug grading (ds) of 0.38, molecule 74 with PubChem ID 2998055 exhibits superior properties with a drug grading (ds) of 0.76. As a whole, the discovered molecules have favorable pharmacokinetics, pharmacodynamics, and drug interaction properties that suggest promising TNF- inhibition and lacked toxicity, suggesting that they are potential drug candidates

Characterization of Sisal Fibre Reinforced Concrete

Experimental characterization of sisal fibre reinforced concrete showed that incorporating fibre into the concrete mixture is beneficial. Optimum performance for a matrix having sisal fibre as reinforcement is at 3% fibre volume fraction (Vff), with 70mm fibre length (Lf) and at a water-cement ratio of 0.6. There is a load increase of 28% from the time the first crack was noticed to the time the beam finally failed and the toughness index for this beam is 2.32.Keywords: Sisal fibre; Concrete beams; Compressive strength; Reinforcement; Toughness inde

Virtual screening and pharmacokinetics analysis of inhibitors against tuberculosis: Structure and ligand-based approach

Life-threatening diseases like tuberculosis have raised concerns in the medical and scientific communities. The damage-causing disease makes the scientific community employ the in-silico approach for design of new inhibitors that can inhibit or retard the havoc caused by this deadly disease. The insilico approach was used in this study to create a mathematical model with promising molecular properties, and receptors from the library were used to screen compounds and estimate the kinetic ability of the screened inhibitors that can cure this disease. 2D molecular properties evolved in the built model with high predictive ability. Three inhibitors x, y, and z emerged with better and higher molecular properties, the lowest binding energy (and higher binding affinity), and a better pharmacokinetic assessment compared to the template used in designing the effective compounds, with binding affinities of -15.56 kcal/mol, -18.51 kcal/mol, and -18.58 kcal/mol, respectively. Virtual screening of these compounds showed that they have good binding energy and excellent docking positions with the inhibiting potential of the receptor. Also, pharmacokinetic predictions and ADMET, depict orally active ability of the inhibitors, possess good human intestinal absorption, and violate none of the RO5 as potential drug candidates to cure this disease. Hence, further laboratory tests are recommended for these to determine their toxicities and biological assays