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

Achieving Pull-in Avoiding Cycle Slip Using Second-order PLLs

Synchronization is an essential process and one of the first tasks of the receiver in case of coherent communications as well synchronous digital data transfer. The phase lock loop (PLL), which employs the error tracking technique, has been a very popular way to implement this synchronizer since the early 1930s. A phenomenon called cycle slip occurs when the number of cycles present in the transmitted carrier (clock) differs from that of the recovered carrier (clock) at the receiver. The cycle slip can be very detrimental to some applications such as frequency modulated communications systems (FSK, multi-carrier etc.), burst digital data transfer, training pulse retrieval, and so on. This paper presents a remedy to avoid the cycle slip by using properly designed second-order Type II PLL.DOI:http://dx.doi.org/10.11591/ijece.v4i2.504

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%

Recovery of Oil From Oil Shale -- An Overall Technological Perspective

The hydrocarbon content of oil shale can be converted into liquid oil which is a possible energy resource for the future. Different aspects of shale oil recovery is briefly discussed. The technology of modified in situ oil shale retorting, which is receiving increasing attention for commercialization, is discussed in a little more detail

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

Frequency and pattern of congenital heart defects among admitted patient in a tertiary care hospital in Bangladesh

Background: Congenital heart disease (CHD) is the commonest of all congenital lesions accounting for nearly 28% of all congenital malformations that have significant impact on morbidity, mortality and heath care cost in children. The aim of study was to determine the pattern of distribution of CHD and the age at which initial diagnosis of CHD was made among children admitted under paediatric cardiology department, Bangladesh Shishu hospital and institute. Methods: This is a descriptive and prospective hospital-based study conducted in the pediatric cardiology department, Bangladesh Shishu hospital and institute. This study included all the patients admitted during January-June 2022 in pediatric cardiology department having confirmed diagnosis of CHD on basis of echocardiographic report. The collected data was entered and analyzed by using statistical package for social sciences v 24.0. Results: Out of 337 patient, 175 patient were male (51.9%) and 162 female (48.1%) with male female ratio of 1.08:1. Total 219 cases (64.9%) were acyanotic CHD and 118 (35.1%) were cyanotic congenital heart lesions. In acyanotic CHD ventricular septal defects (VSDs) constitute 38.8% followed by AV canal defect 6.7%, patent ductus arteriosus (PDA) 3.6%. In cyanotic CHD tetralogy of Fallot (TOF) was the commonest lesion accounted for 28 (8.3%) followed by d-transposition of great arteries 16 (4.7%), pulmonary atresia 15 (4.5%), total anomalous pulmonary venous circulation TAPVC 11 (3.3%), tricuspid atresia 9 (2.7%) and DORV, VSD, PS 10 (2.9%). The commonest combination was VSD with ASD in 15 cases (4.5%). Most of the patient was diagnosed in 1st year of age 280 (83.1%) Conclusions: CHD are very common in our setup and early detection of CHD is increasing. Overall burden of CHD is also increasing therefore a proper population-based study on a large scale is needed to estimate the prevalence accurately

SOCIAL ASPECTS OF FISHERMEN OF COX’S BAZAR IN BANGLADESH

This study was performed at Somiti Para of Cox’s Bazar in order to examine the social issues of fishermen. Sites of the study and number of fishermen (146) were selected purposively. Selected fishermen were interviewed with the help of prestructurred questionnaires. About 20.55% respondents’ age were between 23-27. Among the fishermen, 52.05% were educated at primary level. The study reflects that 61.21% of the respondents had smoking habit. Most of the respondents had various diseases such as 64.38% suffered from cough and cold while 25.43% got fever. Respondents received treatment for the diseases mainly from traditional village doctors. The social status of the respondents were 23.53% lower class, 64.71% lower middle class, 5.88% upper middle class and 5.88% upper class. As the fishermen were poor socio-economic class and education level not satisfactory, special attention should be taken to improve the living condition of this community. Measures should also be taken to lessen their occupational health hazards

Effector vector design in the Phytophthora infestans-potato pathosystem

The oomycete pathogen Phytophthora infestans is the causal agent of the devastating plant disease late blight on potato. Diverse type of transposons and many gene families are present in the genome which encodes the effector proteins involved in causing the pathogenicity. This plant pathogen is predicted to secret hundreds of effector proteins inside the host plant cells to promote infection. These proteins are sensed by the plant immune system in order to prevent pathogen growth. The effector proteins are divided into two main types, cytoplasmic effectors and apoplastic effectors based on their translocated status in the plant cell. In this study, the effectorencoding genes Avr3a, Epi1, Epi10, Inf1 and CRN8 were selected to monitor the potential in planta function of the effectors and to develop a stable transformation procedure for reporter gene constructs with effector gene promoters. The putative promoter sequences were derived from the 5´ regions of the oomycete genes. Primers were designed to amplify the promoter regions and the amplification was confirmed by gel electrophoresis. The reporter gene GFP (encoding green fluorescent protein) was chosen for analysis of their promoter activities and to facilitate studies on spatial and dynamic alteration of gene expression. Cloning was performed using the vector pTOR-eGFP containing a ham34 promoter and a GFP gene. The ham34 promoter was removed and the effector promoters were inserted in its place. A stable transformation procedure was examined using three vectors for the GFP-constructs and the five effector gene promoters. Transformants were obtained at similar frequencies with each combination of effector promoter and GFP; which were confirmed by gel electrophoresis. Subsequently Agrobacterium tumefaciens (C58) mediated transformation was tried for an Avr3a promoter construct. The construct was ligated into the binary vector, but the transformation of Agrobacterium was not successful