Enhancing the Properties of Marl Soils for Effective Construction in Saudi Arabian Region

Marl, containing primarily carbonate (CaCO3) and clays of different percentages with occasional traces of organic matter, silt or sand is usually used as bases and sub-bases for roads and highways. Marl is usually used as sub-grade layers or as a backfill in base and sub-base layers for roads and highways. This type of soil has poor strength and high water sensitivity; a drastic loss of bearing capacity may occur upon immersion.Due to its poor strength and high water sensitivity, appropriate treatment from engineering perspective is necessary before such soils are recommended for use in any construction project. Critical analysis of different stabilization techniques employed in Saudi Arabia for last 30 years has been carried to find the best technique. Mechanical and chemical treatments were found to be more economical than Drainage, dewatering and other techniques. It has been noticed that no study was done in stabilization of Marl Soil using Geo-synthetics technique Hence, it can be an alternate way for future research to improve marl.Marl, containing primarily carbonate (CaCO3) and clays of different percentages with occasional traces of organic matter, silt or sand is usually used as bases and sub-bases for roads and highways. Marl is usually used as sub-grade layers or as a backfill in base and sub-base layers for highway pavements. This type of soil has poor strength and high water sensitivity; a drastic loss of bearing capacity may occur upon immersion. Due to its poor strength and high water sensitivity, appropriate treatment from engineering perspective is necessary before such soils are recommended for use in any construction project effectively. Critical analysis of different stabilization techniques employed for enhancing the marl soil properties in Saudi Arabia for the last 30 years has been carried out to find the best engineering solution. Mechanical and chemical treatments were found to be more economical than drainage, dewatering and other techniques. It has been noticed that no study was done in stabilization of Marl Soil using Geo-synthetics technique Hence, it can be an alternate way for future research to improve marl

Effect of chemical treatments and coupling agents on the properties of unidirectional jute fiber reinforced polypropylene composite

Due to different chemical nature of jute and polypropylene, their blended composite materials often show failures behavior when applied in load bearing purposes. The aim of the research is to improve the properties of unidirectional jute fiber (JF) reinforced polypropylene (PP) composite. Unidirectional fiber composite was produced by simple hot press molding method according to weight percentage of 30wt% filler (JF), 2wt% coupling agent (compatibilizer) degraded PP (DgPP) and maleated PP (MAPP) and 68 wt% matrix (PP). To improve the interfacial interactions between the fiber and PP, the fiber was chemically modified with 10w/v% NaOH, 6w/v% dicumylperoxide (DCPO), 0.05 w/v% K2Cr2O7 and 5 w/v% H2O2 solution. The water absorption, tensile and thermal properties of raw and surface treated fibers composites were compared in particular coupling agent. It has found that the fiber treatments and addition of coupling agents, composites showed better properties. Among the composites, 10 wt/v% NaOH treated jute reinforced PP composite by using MAPP compatibilizer was presented better water absorption and mechanical properties. The positive change of the treated fiber composites was also found in case of the thermal stability that investigated by the TG, DTA and DTG tests

Numerical simulation of periodic MHD casson nanofluid flow through porous stretching sheet

The perspective of this paper is to characterize a Casson type of Non-Newtonian fluid flow through heat as well as mass conduction towards a stretching surface with thermophoresis and radiation absorption impacts in association with periodic hydromagnetic effect. Here heat absorption is also integrated with the heat absorbing parameter. A time dependent fundamental set of equations, i.e. momentum, energy and concentration have been established to discuss the fluid flow system. Explicit finite difference technique is occupied here by executing a procedure in Compaq Visual Fortran 6.6a to elucidate the mathematical model of liquid flow. The stability and convergence inspection has been accomplished. It has observed that the present work converged at, Pr ≥ 0.447 indicates the value of Prandtl number and Le ≥ 0.163 indicates the value of Lewis number. Impact of useful physical parameters has been illustrated graphically on various flow fields. It has inspected that the periodic magnetic field has helped to increase the interaction of the nanoparticles in the velocity field significantly. The field has been depicted in a vibrating form which is also done newly in this work. Subsequently, the Lorentz force has also represented a great impact in the updated visualization (streamlines and isotherms) of the flow field. The respective fields appeared with more wave for the larger values of magnetic parameter. These results help to visualize a theoretical idea of the effect of modern electromagnetic induction use in industry instead of traditional energy sources. Moreover, it has a great application in lung and prostate cancer therapy

Mechanical, thermal and morphological studies of microfibrillated jute/PLA biocomposites

In the present study, biocomposites based on microfibrillated jute (MFJ) fibre and polylactic acid (PLA) have been prepared by solvent-assisted compression moulding techniques. The MFJ is obtained by a sequence of alkali, chlorite and acid treatments of jute fibre. The biocomposites are fabricated by loading of 10, 20 and 30 wt% of MFJ fibre into the PLA matrix. The effect of MFJ fibre loading on the mechanical, thermal, and morphological properties of the composites is also studied. Among these composites, it is observed that 10 wt% fibre-filled biocomposite shows improved tensile strength andtensile modulus compared to virgin PLA film. Similarly, storage modulus and loss modulus are also found improved for the composites. These composites exhibit higher water absorption capacity and lower thermal stability than virgin PLA. The fibre-matrix adhesion is evaluated by scanning electron microscopy. The results are attributed to the improved interfacial adhesion between MFJ and PLA matrix for 10 wt% fibre-filled biocomposites

The STRATAA study protocol: a programme to assess the burden of enteric fever in Bangladesh, Malawi and Nepal using prospective population census, passive surveillance, serological studies and healthcare utilisation surveys.

INTRODUCTION: Invasive infections caused by Salmonella enterica serovar Typhi and Paratyphi A are estimated to account for 12-27 million febrile illness episodes worldwide annually. Determining the true burden of typhoidal Salmonellae infections is hindered by lack of population-based studies and adequate laboratory diagnostics.The Strategic Typhoid alliance across Africa and Asia study takes a systematic approach to measuring the age-stratified burden of clinical and subclinical disease caused by typhoidal Salmonellae infections at three high-incidence urban sites in Africa and Asia. We aim to explore the natural history of Salmonella transmission in endemic settings, addressing key uncertainties relating to the epidemiology of enteric fever identified through mathematical models, and enabling optimisation of vaccine strategies. METHODS/DESIGN: Using census-defined denominator populations of ≥100 000 individuals at sites in Malawi, Bangladesh and Nepal, the primary outcome is to characterise the burden of enteric fever in these populations over a 24-month period. During passive surveillance, clinical and household data, and laboratory samples will be collected from febrile individuals. In parallel, healthcare utilisation and water, sanitation and hygiene surveys will be performed to characterise healthcare-seeking behaviour and assess potential routes of transmission. The rates of both undiagnosed and subclinical exposure to typhoidal Salmonellae (seroincidence), identification of chronic carriage and population seroprevalence of typhoid infection will be assessed through age-stratified serosurveys performed at each site. Secondary attack rates will be estimated among household contacts of acute enteric fever cases and possible chronic carriers. ETHICS AND DISSEMINATION: This protocol has been ethically approved by the Oxford Tropical Research Ethics Committee, the icddr,b Institutional Review Board, the Malawian National Health Sciences Research Committee and College of Medicine Research Ethics Committee and Nepal Health Research Council. The study is being conducted in accordance with the principles of the Declaration of Helsinki and Good Clinical Practice. Informed consent was obtained before study enrolment. Results will be submitted to international peer-reviewed journals and presented at international conferences. TRIAL REGISTRATION NUMBER: ISRCTN 12131979. ETHICS REFERENCES: Oxford (Oxford Tropical Research Ethics Committee 39-15).Bangladesh (icddr,b Institutional Review Board PR-15119).Malawi (National Health Sciences Research Committee 15/5/1599).Nepal (Nepal Health Research Council 306/2015)

Cytotoxicity study of reaction products between isatin and furan

Isatin, 5-chloroisatin, 7-bromoisatin and 7-ethylisatin on treatment with furan in presence of diethylamine yield furan moiety inclusion products bis-diisatin [3,3´] furan, bis-[5,5´] dichlorodiisatin [3,3´] furan, bis-[7,7´] dibromodiisatin [3,3´] furan and bis-[7,7´] diethyldiisatin [3,3´] furan respectively in moderate yields. The cytotoxicity of these compounds was studied by the brine shrimp lethality bioassay and the Structure Activity Relationships (SAR) of these compounds has been discussed. The present study shows that the compound bis-[7,7´] dibromodiisatin [3,3´] furan had pronounced cytotoxicity whereas compounds bis-[5,5´] dichlorodiisatin [3,3´] furan and bis-[7,7´] diethyldiisatin [3,3´] furan were moderately active. It is remarkable that the constituent, Y = -Br at seven position in the benzene ring has greater activity than ethyl and chlorine atom

Cytotoxicity study of reaction products between isatin and furan

Isatin, 5-chloroisatin, 7-bromoisatin and 7-ethylisatin on treatment with furan in presence of diethylamine yield furan moiety inclusion products bis-diisatin [3,3´] furan, bis-[5,5´] dichlorodiisatin [3,3´] furan, bis-[7,7´] dibromodiisatin [3,3´] furan and bis-[7,7´] diethyldiisatin [3,3´] furan respectively in moderate yields. The cytotoxicity of these compounds was studied by the brine shrimp lethality bioassay and the Structure Activity Relationships (SAR) of these compounds has been discussed. The present study shows that the compound bis-[7,7´] dibromodiisatin [3,3´] furan had pronounced cytotoxicity whereas compounds bis-[5,5´] dichlorodiisatin [3,3´] furan and bis-[7,7´] diethyldiisatin [3,3´] furan were moderately active. It is remarkable that the constituent, Y = -Br at seven position in the benzene ring has greater activity than ethyl and chlorine atom

Thermal characterization of chemically treated coconut husk fibre

20-26Effect of chemical treatments using sodium chlorite, sodium hydroxide and acrylamide monomer on thermal behavior of coconut husk (coir) fibre has been studied by means of scanning electron microscopy (SEM) and thermogravimetric analyses (TG, DTG, DTA). A significant variation in fibre surface occurred by chemical treatments is clearly observed in SEM images. The TG and DTA curves show two-stages of decomposition for all the fibres; first below 100°C indicating the moisture loss and the second between 320°C and 360°C due to major degradation of fibre. Chemical treatment increases the thermal stability of fibre through physical and chemical changes. It is found that the temperature below 180°C marginally affects fibre properties, whereas temperature at 180°C significantly decreases tensile strength and degree of polymerization

Computational modelling of multiphase fluid flow behaviour over a stretching sheet in the presence of nanoparticles

Present study analysed hydrodynamic flow behaviour of multiphase radiative Casson and Maxwell fluids with the appearance of nano-sized particles. The impression of a nonlinear chemical reaction is also considered. Firstly, the time-dependent governing equations were computationally resolved using finite difference discretisation methods. Secondly, the convergence analysis with stabilisation of the numerical approach is carried out where the current model has converged for Le ≥ 0.025 and Pr ≥ 0.075. Finally, the impressions of various pertinent parameters are depicted diagrammatically along with tabular analysis on diversified flow fields. The main aim is to define and draw a comparison between Maxwell and Casson fluids on different flow fields. In addition, a comparative study between these two fluids is also newly carried out in this work through the analysis of streamlines and isotherms plotting. Furthermore, the thermal and mass properties found significantly improved mostly in the case of Maxwell fluid. However, Eckert number, Ec, has influenced the temperature field significantly for Casson fluid, and some parameters (Du, Nt, Nb, Le, Pr and Sr) have represented the identical impact on respective fields for both fluids. For the numerical validation, some comparisons are also shown with previous studies and satisfactory agreement is observed

Dynamics of COVID-19 transmission in Dhaka and Chittagong: Two business hubs of Bangladesh

Background: Having inadequate health care systems and poor socio-economic infrastructure, Bangladesh has been braving to contain the impact of current COVID-19 pandemic since March, 2020. To curb the diffusion of COVID-19, the local government has responded to the outbreak by enforcing a set of restricted measures on economic and social activities across the country. Objectives: Here, we aim to assess the propagation of COVID-19 by estimating the coronavirus active cases and mortality rate in two major business hubs of Bangladesh, namely Dhaka and Chittagong city under flexible lockdown conditions. Methods: We apply a data-driven forecasting model using Susceptible, Exposed, Infected, Recovered and Deaths status through time to deal with coronavirus outbreak. Results: The epidemiological model forecasts the dire consequences for Dhaka city with 2400 death cases at the end of December, 2020, whereas Chittagong city might experience 14% more deaths than Dhaka if the severe restrictions are not implemented to control the pandemic. Conclusion: Although lockdown has a positive impact in reducing the diffusion of COVID-19, it is disastrous for human welfare and national economies. Therefore, a unidirectional decision by the policymakers might cost a very high price on either way for a lower-middle-income country, Bangladesh. In this study, we suggest a fair trade-off between public health and the economy to avoid enormous death tolls and economic havoc in Bangladesh