Determination of equilibrium isotherms and proper mathematical model for lime slices

Equilibrium moisture content (EMC) at different air relative humidity and temperatures is a vital parameter in optimization of drying and storage processes. In the present study amount of moisture content in lime (Local variety) slice at different ambient temperatures of 30°C, 40°C and 50°C were measured using gravimetric method. The obtained E.M.C experimental values were employed to plot the isotherm curve at different environmental air temperatures. These data also were fed to fourteen popular mathematical models. The well-known statistical factors such as Coefficient of determination (R^2), Chi-square (χ2), Root of mean square error (RMSE) and Mean of relative deviation (MRD) were calculated to validate the goodness of fit. The Peleg Model was selected as the best model for predicting the EMC at each three temperatures level. The result of present research displayed that the amount of EMC decreased with increasing the ambient temperature. The monolayer moisture content (m0) was also determined using Brunauer, Emmett and Teller (BET) equation. The monolayer moisture content values were 0.023, 0.021 and 0.014 g.H_2 O/g solid at 30°C, 40°Cand 50°C, respectively, and the corresponding constant values of the Brunauer, Emmett and Teller equation were found to be −4.925, −6.543 and −7.035, respectively

The Necessity of The Consideration of Permeability Modifier in Simulations of Clay Treatment Systems Incorporating PVDs and Surcharge

Three trial embankments as TS1, TS2, and TS3 that were built for the investigation of a soil treatment project in Bangkok were modeled and verified based on the reported data. To clarify the importance of integration of the hydraulic modifier function vs stress, in the verified models, the modifier functions were omitted and the FEM models were run in the absence of the function. It was shown that after the omission of the hydraulic modifier, the results were overestimated especially for the TS1 and TS2, which had smaller PVDs (prefabricated vertical drains) distance. For the TS1 embankment, the settlement increased from 0.78 m to 0.87 m in 210 days. In 365 days, the settlement increased from 1.27 m to 1.44 m. For the TS2 embankment, the settlement increased from 0.93 m to 1.67 m in 230 days. In 410 days, the settlement increased from 1.36 m to 2.27 m. For the TS3 embankment, the settlement increased from 1.15 m to 1.79 m in 230 days. In 410 days, the settlement increased from 1.52 m to 2.24 m. The inclusion of the hydraulic function that calibrates the model for every step of loading is essential in the modelling such problems. For the design phase, this function should be calculated from lab tests, preferably undisturbed samples that were bored from the site, and the resultant function be used as an inseparable part of modeling and calculations.Journal of Civil Engineering and Materials Applicatio

Uniaxial Tensile Stress-Strain Relationships of RC Elements Strengthened with FRP Sheets

The shear behavior of fiber-reinforced-polymer–strengthened reinforced concrete (FRP-strengthened RC) members is not fully developed and accurately predicted because of the lack of accurate constitutive laws for the components of the composite members. This paper presents experimental and analytical investigations of tensile stress-strain relationships of concrete and steel in FRP-strengthened RC members. These stress-strain relationships are required in formulations of softened truss models to predict the shear behavior of the FRP-strengthened RC element. Thirteen full-scale FRP-strengthened RC prismatic specimens with different FRP reinforcement ratios, steel reinforcement ratios, and FRP wrapping schemes were tested under uniaxial tension loading. The results show that the tensile behavior of the concrete and steel is altered because of the externally bonded FRP sheets. Modified constitutive laws are proposed and incorporated in the softened membrane model (SMM) to demonstrate through two tests the behavior of FRP-strengthened RC element subjected to pure shear. Moreover, crack spacing and crack width were studied and compared with existing code provisions

Cracking behavior and crack width predictions of FRP strengthened RC members under tension

This paper presents and discusses the experimental results of uniaxial tensile tests of fiber reinforced polymer externally strengthened reinforced concrete (FRP strengthened RC) prisms in terms of crack width and crack spacing. As a non-contact and material independent system for in-time measurement of displacement and strain, the digital image correlation (DIC) technique has been used in this study for investigating the evolution of strains and formation of cracks during uniaxial tensile tests. As a result, the cracks were measured precisely at any load stage. The experimental results of tests performed by authors and other researchers on FRP strengthened RC members in tension are compared to prediction models from code provisions and guidelines (Eurocode 2 and fib 14), and their suitability are analyzed and discussed. The results show the dependence of the behavior and crack characteristics of FRP strengthened RC members to parameters such as wrapping scheme and FRP reinforcement ratios which are not included in design provisions for crack analysis. A new formulation for predicting crack width and spacing in FRP strengthened RC members, calibrated using the experimental results, has been proposed which considers all the main affecting parameters

Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017

A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1–70.8) million) to 6.4% (58.3 (47.6–70.7) million), but is predicted to remain above the World Health Organization’s Global Nutrition Target of <5% in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8–38.5) million) in 2000 to 6.0% (55.5 (44.8–67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic

Behavior of FRP Strengthened Concrete Panel Elements Subjected to Pure Shear

Several investigations have revealed that many aging civil engineering structures such as highway bridges are structurally deficient and need repairs and/or retrofitting. Among various solutions, fiber reinforce polymer (FRP) composites have shown a promising solution and have been increasingly used in rehabilitation and strengthening of reinforced concrete (RC) structures. Although, researchers have devoted a tremendous effort on studies related to FRP shear strengthening of RC structures, the state of knowledge shows that the problem is not fully resolved and there are still controversies in the prediction of shear behavior in the presence of FRP. To predict the increase in shear capacity due to FRP strengthening, several analytical models have been proposed. However, when these models are compared using existing experimental database, they show inconsistencies and large scatter in the prediction. This is due in part to the high level of complexity associated with the shear behavior, but more importantly due to the lack of rational constitutive models for FRP shear strengthened elements. This research study aims at establishing the shear constitutive behavior of externally bonded FRP strengthened RC elements subjected to pure shear through experimental investigations and development of associated analytical and finite element models. In order to evaluate such behavior, at the first part of the research, a series of full-scale FRP strengthened RC panels were constructed and tested under pure shear stress field using the University of Houston’s state of the art panel tester. It was found that application of FRP sheets increased the shear capacity of RC panels. Also, the shear behavior of FRP strengthened RC members is influenced mainly by the FRP stiffness, wrapping scheme, and the internal shear reinforcement. Based on the test results, the Softened Membrane Model (SMM), which was developed for reinforced concrete, was modified and extended for application to FRP strengthened RC members. The second part of this research involved the development of a computer program for analysis of FRP strengthened RC structures. The constitutive laws of FRP strengthened RC members, developed through previous research at UH, have been implemented into the finite element frame work OpenSees to predict the behavior of FRP strengthened RC panels and beams under monotonic loading. The analytical model was tested and validated using existing experimental data. Furthermore, to investigate the serviceability conditions in FRP strengthened RC structures, the crack characteristics of a series of full-scale tensile tests of FRP strengthened RC prisms and test panels have been monitored by using a digital image correlation system. The experimental results were used to calibrate a newly developed equation to calculate crack spacing and crack width in RC elements externally strengthened with FRP.Civil and Environmental Engineering, Department o

"Evaluation of Thermal and Visual Comfort in University Classrooms: The Cases of Two LEED Silver Certified Buildings on the Campus of Texas A&M University

Thermal and visual comfort are often listed by occupants as the most important requirements for indoor environmental quality. Leadership in energy and environmental design (LEED), as an internationally recognized rating system for sustainable buildings, defines credits for the indoor environmental quality including thermal and visual comfort qualities. New designs, pursuing daylighting credits, draw on high window to wall ratios in order to provide natural light, which has also caused glare, closing the blinds, and consequently using artificial lighting during daytime. The high window/wall ratio increases the heat loss, resulting in cold spaces, and increases solar gains, resulting in overheated spaces during the hot seasons. The actual performance of LEED buildings should be assessed in order to define the gap between designed and actual levels of performance. This study, through questionnaire survey and onsite measurement, evaluates the visual and thermal comfort in four classrooms of different window sizes, locations, and orientations in two LEED buildings on the campus of Texas A & M University. The students' actual perceptions are compared through measurements and simulations with metrics proposed in LEED v2, v3, and v4, showing satisfaction with the thermal, though not the visual environment. The results have been discussed for improving the quality of visual environment in university classrooms

Potential Pathogenicity of Candida Species Isolated from Oral Cavity of Patients with Diabetes Mellitus

Introduction. In the recent decade, the increased immunocompromised population such as diabetic patients makes a high incidence of invasive Candida infections. Diabetes mellitus is the most common endocrine metabolic disorder, and diabetic patients are more susceptible to oral candidiasis infection. Candidiasis is an opportunistic fungal infection caused by many species of Candida. Secretion of exoenzymes plays an important role in the virulence and pathogenesis of Candida species. The aim of this study was to evaluate the potential role of phospholipase, esterase, and hemolytic activity of Candida species isolated from oral cavity lesions of diabetic patients. Methods. A total of 108 Candida species including 75 Candida albicans and 33 non-Candida albicans species were recovered from the oral cavity of diabetic patients included in our study. Egg yolk agar, Tween 80 opacity medium, and blood agar plate assays were used for determining phospholipase, esterase, and hemolytic activities, respectively. Results. Candida albicans species had the most exoenzyme activity in comparison to non-albicans isolates. Candida albicans isolates showed 97.3%, 100%, and 77.3% phospholipase, hemolysin, and esterase activities, respectively. The difference between Candida albicans and non-Candida albicans was significant in phospholipase (P<0.001) and hemolytic activity (P=0.027), but not significant in esterase activity (P=0.076). Conclusion. This study showed that most of the isolates had different enzymatic patterns, and Candida albicans isolates had the most exoenzyme activity. So due to the potential effects of these enzymes in pathogenesis and virulence effects of Candida species, we can conclude that the severity of extracellular enzymes may play a role in the severity of signs and symptoms of Candida oral cavity infections in diabetic patients

The comparison of system reliability indices among presented models, annual form of dynamic game, PSDNG and BSDP model.

<p>The comparison of system reliability indices among presented models, annual form of dynamic game, PSDNG and BSDP model.</p

The volumetric reliability of the reservoir system associated with different models for Zayandeh-Rud river system.

<p>The volumetric reliability of the reservoir system associated with different models for Zayandeh-Rud river system.</p