The Energy and Exergy Analysis of the Reactor Unit of Boric Acid Production Process with ChemCAD Simulation

Energy and exergy analysis of systems are of great importance to enhance the energy and exergy efficiency of industrial production facilities. With the energy and exergy analyses performed, the energy dependency of the production facilities and their energy consumption can be reduced, the price of the product can decrease, and the profit margin can increase. Additionally, it is ensured that the energy produced based on fossil fuels is used in a controlled way. In the present study, the analysis of energy and exergy has been performed for the production reactor unit of the Boric Acid from Colemanite. The first law of thermodynamics and ChemCAD simulation program was used for energy analysis calculations, and the calculations of exergy analysis were carried out by using the second law of thermodynamics. The total energy loss of the reactor unit and the calculated energy loss per 100 kcal input steam were calculated as 110880 kcal/h and 3.724%, and the losses of total exergy in the reactor units and the losses of exergy calculated per 100 kcal input steam were calculated as 225058.86 kcal/h and 30.095%, respectively. Exergy efficiency for the reactor unit has been determined as 3.3 %. Some suggestions were given for the reactor units of boric acid production plants to minimize system losses.

Geotechnical Characteristics of Benin Formation, Owerri Imo State, Nigeria

A good road network consists of a constant stretch of asphalt laid down for a smooth ride. The spot in the smooth ride on the pavement is commonly referred to as "pavement failure." Soil type, load bearing capacity of materials, zone of vulnerability, resistance to permeation, compressibility, shrinkage limit, and other details are frequently required in order to construct a very good and solid foundation for the planned bridge site. In Nigeria, numerous factors contribute to the failure of road construction projects. They are primarily insufficient research on subgrade and other pavement materials (sub-base and base courses) prior to the start of road projects; flawed engineering, including a poor drainage system and supervision throughout road construction; and shoddy workmanship that was superimposed with asphaltic concrete to improve strength. Within the Niger Delta basin, the study area is located between latitude 5.485°N and longitude 7.035°E. The Benin Formation underpins the study area. It is composed primarily of friable sands, conglomerates, very coarse sandstone, and isolated gravel units, as well as intercalation of Pliocene to Miocene shale/clay lenses. Natural Moisture Content (NMC), Linear Shrinkage (LS), Particle Size Distribution, and California Bearing Ratio were among the laboratory tests performed on samples collected at failed and stable sections of some selected road segments (CBR). When compared to the stable sections, the NMC along the failed sections was on the high side (ranging from 13.11 percent to 26.89 percent) (ranging from 11.11 percent to 16.40 percent). The majority of the tested soils passed the 0.075mm sieve with a percentage greater than the Federal Ministry of Works and Housing's maximum of 35% for subgrade materials. The maximum dry density (MDD) for the samples at failed and stable sections was 1550 kg/m3 to 1860 kg/m3; 1650 kg/m3 to 1980 kg/m3; and the Optimum Moisture Content (OMC) was 8.30% to 20.30%. The soaked CBR values ranged from 2 to 17 percent, while the unsoaked values ranged from 4 to 25 percent.

Municipal Solid Waste Disposal Site Selection Using Remote Sensing Technology and AHP Process (Case Study: Khesht city, Fars Province, Iran)

The design and implementation of the municipal waste management system aim to solve the urban issues and ultimately contribute to the citizens' health and welfare. The first step in this system is to select a site for the safe disposal of wastes. This survey aimed to select the most suitable landfill site for municipal solid waste using the geographic information system (GIS) and the analytic hierarchy process (AHP) model following the environmental, economic, and engineering criteria. Therefore, by reviewing the literature and backgrounds, the parameters required for locating the landfill site were extracted, and the most important ones (15 sub-criteria) were selected and divided into four groups. The results showed that the sub-criterion of distance to the river with the weight of 0.218 was identified as the most critical parameter, followed by groundwater depth. In this way, the flooding parameter with the weight of 0.010 was considered the least important variable. In addition, it was found that the moderate suitability class with 50% of the area had the highest area, and the very high suitability with 0.8% had the lowest area. The inconsistency rate was equal to 0.04, which illustrates the high consistency of matrices. Then, the overlaying was carried out, and three sites were determined as the best place for a landfill in Khesht county.

Assessment of Thermophysical and Mechanical Properties of Composite Panels Fabricated from Untreated and Treated Coconut Husk Particles for Structural Application

Large quantities of coconut husks generated are under-utilized. In developing countries, this situation warrants their disposal by open burning or indiscriminate dumping. Either practice adversely affects the environment and public health. In this study, test samples were fabricated from untreated coconut husk particles (UCP) at 0%, 25%, 50%, 75%, and 100% weight proportions with treated coconut husk particles (TCP) using epoxy resin as binder. Five representative samples were prepared per formulation and then subjected to various intended tests. The test results revealed water absorption, bulk density, thermal conductivity, specific heat capacity, thermal diffusivity, nailability, flexural strength, and compressive strength to be (24.88 ± 0.04) %, (459.78 ± 0.05) kgm-3, (0.0867 ± 0.0001) Wm-1K-1, (1573.76 ± 1.14) Jkg-1K-1, (1.198 ± 0.002) x 10-7 m2s-1, (100.0 ± 0.0) %, (11.94 ± 0.03) N/mm2, and (22.86 ± 0.04) N/mm2 respectively for the control sample with UCP content. Also, the respective values of the properties were (29.05 ± 0.06) %, (583.87 ± 0.05) kgm-3, (0.1009 ± 0.0002) Wm-1K-1, (1402.66 ± 1.45) Jkg-1K-1, (1.232 ± 0.004) x 10-7 m2s-1, (100.0 ± 0.0) %, (14.58 ± 0.03) N/mm2, and (33.27 ± 0.02) N/mm2 for the counterpart sample containing the TCP. All the samples showed better tendencies for thermal insulation performance compared to conventional ceilings like plywood, PVC, and asbestos. Thus, utilization of coconut husks as described in this study could alternatively help to solve the disposal problems of such wastes while availing building industries with suitable raw materials to manufacture cost-effective heat-insulating ceilings.

Finite Difference Method in Fluid Potential Function and Velocity Calculation

There is no deterministic solution for many fluid problems but by applying analytical solutions many of them are approximated. In this study an implicit finite difference method presented which solves the potential function and further expanded to drive out the velocity components in 2D-space by applying a point-by-point swiping approach. The results showed the rotational behavior of both potential function as well as velocity components while encountering central obstacle.

Suitability Assessment of Construction and Demolition Waste as a Highway Material

For Being a developing country urbanization is growing rapidly in Bangladesh and there has been a significant increase in the construction of roads. But due to lack of financial aid many of the roads are still unsealed. However, not only the utilization of Construction and Demolition Waste (CDW) in flexible pavement will be helpful for the reduction of road construction costs but also it will help to reduce environmental pollution which may be caused by disposing CDW in open area. The objective of this research is to utilize the CDW in base and sub base layers in the flexible pavement design to reduce the cost of road construction and environmental pollution. Proceeding by collecting CDW like brick from demolished building and conventional brick from kiln, a no of standard test conducted in laboratory namely Aggregate Impact Value, Crushing Value, Specific Gravity, Water Absorption and Loss Angeles Abrasion Test for three times. After analyzing the test results, we found that the average Aggregate Impact Value for CDW and Conventional Aggregate (CA) are respectively 29.52% and 23.87%, Aggregate Crushing value for CDW and CA are respectively 28.10% and 22.88%, Los Angeles Abrasion value for CDW and CA are respectively 31.47% and 28.52%, specific gravity value for CDW and CA both is 1.75, water absorption for CDW and CA are respectively 7.62% and 12.23%. After analyzing the test results and comparing with the standard value, we figure out that the CDW are useful for using base and sub base layers in the flexible pavement.

Study on the Impact of “Gerayo Amahoro Policy” on Road Traffic Accidents Reduction in Rwanda

The global status report on road safety declared that the number of annual road traffic deaths has reached 1.35 million. In Rwanda, considering the raising number of vehicles in line with the economy growth and the above 48.90/000 ratio of deaths per registered vehicles; the lives of people are therefore increasingly exposed to road traffic crashes. This study therefore aims to utilize statistical methods for assessing the impact of Gerayo Amahoro policy on Road Traffic Accidents reduction in Rwanda and propose counter measures that could help the decision makers in minimizing the losses caused by Road Traffic Accidents. secondary data related to road traffic accidents have been collected by using questionnaire from Rwanda National Police with the study period from 2016 up to 2020 inclusive. Analysis was done by using graphics and chi-square methods in excel and SPSS software. The results indicated that GERAYO AMAHORO policy plays the greatest role in reduction of RTAs in Rwanda due to the number of RTAs happened before the implementation of GERAYO AMAHORO which was high as compared to the total number of RTAs after implementation of GERAYO AMAHORO policy. This research conclude that negligence, over speed, bad maneuver and over drunk are mostly causes and responsible for the occurrence of RTAs in Rwanda; indicated that Vehicle types mostly related to RTAs were moto-cycles, cars and 4 wheel vehicles and the mostly victims related to RTAs were moto-cyclists, passengers and pedestrians.

GTN Damage Modelling of the AA6063 Using Image Processing

In this paper, an innovative way of calculating the Gurson–Tvergaard–Needleman parameter has been developed for AA 6063. AA 6063 is an aluminum alloy comprising the alloying ingredients magnesium and silicon. The Aluminum Association maintains the standard that governs its composition. It has strong mechanical properties and may be heat treated and welded. Image processing technique has been used to calculate the damage constant for the AA 6063. The image of the sample has been taken under a microscope of undeformed and fractured material. Then the images are analyzed using the Open CV tool in a python open-source environment. The initial and final void fraction of the sheet has been calculated. Damage models, particularly the Gurson–Tvergaard–Needleman (GTN) model, are widely used in numerical simulation of material deformations. Each damage model has some constants which must be identified for each material. The direct identification methods are costly and time-consuming. A combination of experimental, numerical simulation and optimization have been used to determine the constants in the current work. Numerical simulation of the dynamic test was performed utilizing the constants obtained from quasi-static experiments. The results showed a high precision in predicting the specimen's profile in the dynamic testing.

Correlating the Strength Properties of Roller Compacted Concrete

Prediction of the strength properties of roller compacted concrete from mathematical models is significant for rapid decision of the quality of the pavement. In the present assessment, roller compacted concrete slab samples have been prepared in the laboratory using 12 percentage of Portland cement by weight of aggregates. Cube, core, and beam specimens were extracted from the slab samples and tested for compressive, indirect tensile, and flexural strength at the age of 28 days. Strength test results were corelated among each other and mathematical models were obtained. It was observed that low significance of aggregates gradation type on the compressive and tensile strength exists. However, high influence of dense gradation on flexural strength could be detected. The flexural strength of dense graded mixture is higher than that of gap graded mixtures. The compressive strength of gap graded mixture is higher than that of dense graded mixture. It can be concluded that the flexural strength is higher than the tensile strength by (2.17 and 1.24) folds for dense and gap graded mixtures respectively. The compressive strength is higher than tensile strength by (5.72 and 4.87) folds for dense and gap graded mixtures respectively. The compressive strength is higher than the flexural strength by (3.4 and 2.49) folds for dense and gap graded roller compacted concrete respectively. The obtained mathematical models exhibit high coefficient of determination and may be implemented in verification of the specific strength property based on other measured strength properties of roller compacted concrete.

Boundary Value Problems of Thermoelasticity for Porous Sphere and for A Space with Spherical Cavity

This article is concerned with the coupled linear quasi-static theory of thermoelasticity for porous materials under local thermal equilibrium. The system of equations is based on the constitutive equations, Darcy's law of the flow of a fluid through a porous medium, Fourier's law of heat conduction, the equations of equilibrium, fluid mass conservation and heat transfer. The system of governing equations is expressed in terms of displacement vector field, the change of volume fraction of pores, the change of fluid pressure in pore network and the variation of temperature of porous material. The present paper is devoted to construct explicit solutions of the quasi-static boundary value problems (BVPs) of coupled theory of thermoelasticity for a porous elastic sphere and for a space with a spherical cavity. In this research the regular solution of the system of equations for an isotropic porous material is constructed by means of the elementary (harmonic, bi-harmonic and meta-harmonic) functions. The basic boundary value problems (the Dirichlet type boundary value problem for a sphere and the Neumann type boundary value problem for a space with a spherical cavity) are solved explicitly. The obtained solutions are given by means of the harmonic, bi-harmonic and meta-harmonic functions. For the harmonic functions the Poisson type formulas are obtained. The bi-harmonic and meta-harmonic functions are presented as absolutely and uniformly convergent series.