Design of ballasted railway track foundations using numerical modelling with special reference to high speed trains

A new design method for ballasted railway track foundations was developed based on improved empirical models and sophisticated three-dimensional finite element numerical analyses. The method was developed in the form of simple design charts for use by practitioners. The results obtained from the method were found to be in an excellent agreement with the field observations, and the method is expected to provide a significant contribution to the current railway tack design code of practice

Lubrication Performance of Vegetable Oils Modified with Halloysite Clay Nanotubes (HNT) as Lubricant Additives

Vegetable oil-based nano-lubricants are a great alternative to petroleum-based lubricants because of their less adverse impact on the environment. This work evaluates the tribological performance of sunflower, corn, and peanut oils modified with halloysite clay nanotubes (Al2Si2O2(OH)2nH2O) as lubricant additives at different concentrations. To analyze the tribological performance of the nano-lubricants, a block-on-ring tribometer was used following the ASTM G-077-17 standard procedure. Characterization of HNT was carried out by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Thermogravimetric Analysis (TGA). The effect of the HNT on the lubrication performance of the newly developed vegetable oil-based nano-lubricants was evaluated, and the experimental data of wear, friction, and temperature was analyzed. The results concluded that sunflower, peanut, and corn oils modified with Halloysite Clay Nanotubes could be a great alternative to mineral and synthetic lubricants

ACTIVATION SCAVENGING OF AEROSOL : EFFECT OF TURBULENCE AND AEROSOL-COMPOSITION

The interaction of aerosol particles with solar radiation significantly contributes to the global radiation balance. The magnitude of this aerosol-radiation interaction, among other parameters, depends on different aerosol properties, including how readily these particles would act as cloud condensation nuclei (CCN). These properties are governed by the formation and scavenging processes of aerosol. This dissertation explores some of these scavenging processes. Favorable humidity and preexisting aerosol particles acting as CCN are the sine qua non conditions to form cloud droplets in Earth’s atmosphere. Forming cloud droplets (known as activation), meanwhile, acts as a wet scavenging mechanism for those CCN. Given the required humidity, size, and chemical composition of an aerosol particle, determine its probability to activate. Through targeted experiments in a cloudy, turbulent environment in Michigan Tech’s Π chamber, we show that turbulent fluctuation blurs correspondence between activation and a particle’s size and chemical composition. We also show that turbulence enhances the activation efficiency and can mimic the effect of heterogeneity in the size and chemical composition of the aerosol particles. In the absence of clouds, we discuss how turbulence affects the dry scavenging of aerosol particles. Finally, we propose an operational protocol to improve the temporal resolution of an instrument that counts the number of CCN present in an environment as a function of supersaturation (i.e., relative humidity \u3e 100%

A mechanistic approach For predicting the effect of various factors on partitioning between free and bound chlorides in concrete

The chloride-induced corrosion of reinforcing steel in concrete structures has become a widespread durability problem throughout the world. When concrete structures come in contact with chloride sources, the chloride ions will diffuse through the body of the concrete and ultimately reach the steel. Not all of the chloride ions which penetrate the concrete remain free in the pore solution. Some of the ions become bound to the hydration products in a chemical reaction to form calcium chloroaluminate hydrate (Friedel' salt). It is also well known that only the portion of the chloride ions that remains free is responsible for causing damage to the concrete structures by corroding steel rebar. Thus, the chloride binding capacity of the cementitious matrix plays a major role in controlling chlorides ingress and, consequently, the corrosion of steel reinforcement in concrete. The chloride binding capacity is affected by cement composition, environmental factors, and by the source of the chlorides ( vs. ). To quantify the durability of new and existing structures, a clear understanding of the mechanisms of chloride penetration into the concrete cover is required. Currently, most of the models available in the published literature for calculating free chloride ions in concrete use Fick’s law for chloride transport and chloride binding isotherms to account for bound chlorides. Binding isotherms are cement and environment specific. Thus, the existing models cannot be used for all types of cement and variable general environmental exposure conditions such as temperatures, pH levels, and chloride sources. A general mechanistic approach that can overcome those limitations is proposed in this thesis based on the concepts of ion-exchange theory for an accurate determination of chloride ingress in concrete under variable environmental conditions. Some of the model input parameters, such as exchange capacity and the equilibrium constant for the exchange reaction, were not easy to determine directly from experiments and were determined through an inverse modeling procedure. Verification experiments were carried out by varying different environmental parameters and making comparisons with the simulated results using the corresponding parameters. The experimental results showed that the proposed procedure is able to predict the amount of free chlorides in concrete, including predictions of chloride binding as a function of pH, temperature, chloride sources, and the presence of other ions such as carbonate. The proposed model was also used to clarify some unresolved issues such as the effect of chloride sources on binding and the effect of pH on the release of bound chlorides in the presence of carbonation

Person independent classification of facial expressions using multi-class support vector machines

This thesis describes a fully automated computer vision system for detection and classification of the seven basic facial expressions using Multi-Class Support Vector Machines (SVM). Facial expressions are communicated by subtle changes in one or more discrete features such as tightening the lips, raising the eyebrows, opening and closing of eyes or certain combination of them, which can be identified through monitoring the changes in muscles movements (Action Units), located around the regions of mouth, eyes and eyebrows. An analytic representation of face with fifteen feature points describing the geometric and physical (muscle) model of facial expression structure has been used that represents and identifies the principal muscle actions and also provides visual observation (sensing) of the discrete features responsible for each of the seven basic human emotions. Feature points from the region of mouth have been detected by segmenting the lip contour applying a newly introduced variational formulation of the existing level set method. In addition, a multi-detector approach of facial feature point detection has been utilized for identifying the points of interest from the regions of eyes, eyebrows and nose. The feature vector composed of fifteen features is then obtained with respect to the average representation of neutral face by calculating the degree of displacement of five different pairs of points, and measuring the deviations of ten points from a non-changeable rigid point. Finally, the obtained feature sets are used to train a Multi-Class SVM classifier. The proposed automated facial expressions classification system has been tested extensively on two publicly available facial expression databases and 92.04% and 86.33% of average successful classification rates have been achieved. Besides, satisfactory results have been obtained by comparing the proposed method with other previous methods of facial expression classification

In-vitro antimicrobial activity of methanolic extract of Ficus racemosa Linn. fruits

Abstract The antimicrobial activity methanol extracts of Ficus racemosa Linn., belonging to the family Moringaceae, was determined in vitro, using disc diffusion method against human pathogenic bacteria fungi. The displayed a potential antibacterial activity against all the tested four Gram negative and Gram positive bacteria: Staphylococcus aureus, Bacillus subtilis, Vibrio cholera, Bacillus cereus, Salmonella typhi, Shigella dysenteriae, Pseudomonas aeruginosa, Klebsiella species and Proteus species as well four fungi: Alternaria spp., Colletotrichum spp., Curvularia spp. and Fusarium spp. The highest zone of inhibition was found in the concentration of 200 µg/disc for Staphylococcus aureus (18mm) and in the concentration of 150 µg/disc for Fusarium spp. (12mm). The consequences of this investigation suggest that the extracts of Ficus racemosa can be used to discover antibacterial agent for developing new pharmaceuticals to control studied human pathogenic bacteria responsible for severe illness

Evaluation of microbiological quality of dried baim (Mastacembelus armatus) in Bangladesh

A study was performed for five months to assess the microbiological quality of dried Baim (Mastacembelus armatus) in Sylhet region of Bangladesh. A total of 45 dried samples were randomly collected on monthly basis from three different sources of Sylhet region; one from producer (drying yard of Lamagaji) and others from retail market (Bandar Bazar) and control (prepared in laboratory). The mean total plate count (TPC) of dried Baim from producer, retail market and control were observed 6.20 ± 0.72 ×105, 9.64 ± 1.58 ×105 and 1.61 ± 1.06×105 cfu/g, respectively, whereas, average total fungal count (TFC) were estimated 3.77 ± 0.81 ×103, 4.65 ± 1.08 ×103 and 1.78 ± 0.64 ×103 cfu/g, respectively. TPC and TFC of dried Baim of retail market were found significantly (P<0.05) highest and significantly (P<0.05) lowest in control samples than others. Twenty five samples from each source were analyzed to determine pathogenic E. coli and Salmonella sp. Hundred percent samples of dried Baim of producer and retail market were found contaminated by E. coli whereas; the controlled samples were free of E. coli. Likewise, the dried Baim samples of producer and retail market were contaminated 60% and 80% respectively with Salmonella. Dried baim sample from market was 100%, producer sample was 62% and control sample was 32% contaminated with fungi. The most common fungus species in samples were Aspergillus fumigatus, Fuserium proliferatum and Rhizopus stolonifer. The overall microbiological quality of control samples was comparatively better than the commercially produced dried Baim in Sylhet region

Quality assessment and shelf-life of processed tilapia (Oreochromis niloticus) fish sticks: Laboratory based study

Customers prefer tilapia (Oreochromis niloticus), one of the most popular freshwater fish species farmed in Bangladesh, because of its flavor and affordable market pricing. This study aimed to develop value-added tilapia fish sticks and evaluate the quality changes, shelf life, and storage stability of the developed tilapia fish sticks in order to investigate the possibilities of better utilizing low-value tilapia fish and to satisfy consumers' growing demand for quality ready-to-eat food products. For this regard, storage characteristics in room (28ºC) and refrigerator (5ºC) temperatures were assessed in terms of microbiological, chemical, proximate, and sensory attributes. The moisture, lipid, protein, and ash contents of the fish sticks were observed to be 56.23±0.62, 7.62±0.27, 26.01±0.39, and 2.93±0.23%, respectively, at fresh condition. As storage time increased, it was discovered that ash content at room temperature increased while moisture, lipid, and protein levels steadily declined. On the other hand, it was discovered that at refrigeration temperatures, ash and fat content increased while moisture and protein content decreased. Compared to fish sticks held at ambient temperature, changes in the proximate composition of fish sticks stored in a refrigerator were found to be more stable. TVB-N was initially measured as 12.38±0.45 mg/100 g. After 24 hours of room storage, the TVB-N value exceeded the acceptable level; however, after 72 hours of refrigeration, it did not exceed the acceptable limit and was deemed fit for consumption. TPC was observed in fresh fish sticks as 3.74±0.31 Log CFU/g. In 48 hours at room temperature, the bacterial load of tilapia fish sticks increased sharply (p<0.05) during the course of the storage period and went above the microbiological threshold for fishery products (7 Log CFU/g of flesh). The bacterial growth trend was slower and, after 72 hours, was within the permitted limit at refrigerated storage temperature. All fresh products had the highest initial sensory ratings. At ambient temperature, all of the products sensory qualities significantly declined with time (p<0.05), however at refrigeration temperature, the product was determined to be more stable. The overall acceptability score assessed for appearance, flavor, taste, and texture was within acceptable limits for up to 24 hours at room temperature, but not for 72 hours at refrigeration temperature. According to the study's findings, tilapia fish sticks have a very limited shelf life at room temperature (28°C), only lasting around 24 hours, whereas they can last up to 72 hours at 5°C in the refrigerator