Unsaturated shear strength properties of a compacted expansive soil from Regina, Canada

Abstract The main objective of this research was to investigate the unsaturated shear strength properties of the compacted expansive soil from Regina (Saskatchewan, Canada). Laboratory investigations on a typical expansive clay (liquid limit of 77% and plastic limit of 27%) were conducted using both saturated and unsaturated samples. Results indicated that the SWCC had one AEV of 10 kPa for w and θ and two AEVs for S: 10 and 7000 kPa due to drainage through inter-clod pores and soil matrix, respectively. Most of the shrinkage occurred around S ≈ 80%, whereas desaturation before and after this value was associated with small changes in void ratio. Likewise, the peak stress on the dry side of optimum along with the initial gradient of the stress-displacement curve of up to 250 kPa and 13,350 kPa/mm, respectively, decreased to 170 kPa and 5670 kPa/mm on the wet side of optimum. The variation in cohesion followed the compaction curve and increased from 24 kPa on dry side to 65 kPa at optimum and then decreased to 33 kPa on wet side. The friction angle followed an L-shaped trend and decreased from 44° on dry side to 29° at optimum and to 27° on wet side. Finally, the S-shaped ϕ b curve was in agreement with compaction characteristics and the SWCC. The ϕ b curve comprised 1° increase on dry side (and approaching residual suction), 12° increase around optimum (between AEV and residual suction), and 2° increase on wet side that tended to approach ϕ near saturation.</jats:p

Evaluating refrigeration and antibiotic treatment for maintaining urine electrophysiology.

BackgroundElectrophysiological analysis of urine has shown utility in differentiating between healthy and bladder cancer specimens, offering a rapid, label-free alternative to molecular methods. However, transporting and preserving urine samples from collection to the laboratory poses logistical challenges that could impact the reliability of electrophysiological measurements.ObjectiveThis study investigates the effects of prolonged refrigeration on the dielectric properties and ζ-potential of urine specimens and evaluate whether antibiotic treatment can enhance sample preservation without altering electrophysiological properties. A new methodology to evaluate urine specimen quality and determine bacterial contamination, using electrophysiological modalities, is presented.MethodsMid-stream urine samples from healthy participants (n =  4) were collected and divided into untreated and 1% penicillin/streptomycin-treated groups. Samples were analysed at baseline prior to storage at 4°C, with further analysis every 24 hours for 96 hours. Changes in dielectrophoresis (DEP) response and ζ-potential were measured using a 3DEP cytometer (Deparator, UK) and Malvern Panalytical Zetasizer Nano ZS90 (Malvern, UK), respectively. Chemical analyses, including pH and nitrite levels, and microscopic examinations were also conducted.Results & limitationsSignificant electrophysiological changes were observed in both untreated and antibiotic-treated urine samples over time. Both groups showed a linear increase of change in DEP response and ζ-potential values, from baseline over time. Untreated samples exhibited significant deviations in DEP and ζ-potential from baseline after 48 hours, with significance at 72 hours (P ConclusionProlonged refrigeration can maintain the quality of urine samples for up to 48 hours with antibiotic treatment. Current UK and European guidelines recommend urinalysis within 24 hours of specimen collection; the findings of this study support the use of DEP and ζ-potential analysis as practical clinical tests in a mail-in screening setting, provided appropriate sample preservation measures are taken

A comprehensive review on the assessment of fuel additive effects on combustion behavior in CI engine fuelled with diesel biodiesel blends

Development in transport technology is a major issue owing to the increase the number of vehicles, which in turn increases emissions, which result in global warming. The world’s present transportation systems are greatly dependent on petroleum which will deplete rapidly due to limited reserves of fossil fuel. In addition, transportation is responsible for more than 25 percent of the world’s greenhouse gas (GHG) emissions, and this share is rising, which is a threat for future. As an alternative, biodiesel has drawn attention due to its renewability, biodegradability, high conductivity, low sulfur content, flash point, low aromatic content, increased lubricity etc. with less carbon monoxide and carbon dioxide emission. On the other hand, as the viscosity of biodiesel is greater than diesel due to its higher molecular mass and chemical structure, problems such as pumping, combustion, atomization in the injector system, injector deposit, plugging of filters, carbon deposits on piston and head of engine occur. Most previous studies concluded that although particulate emissions from biodiesel fuelled engines are much less than in gasoline, NOx emissions increases significantly. The adjustment of ignition delay in the premixed combustion phase, faster rate of fuel burn, advanced start of combustion, low radiation heat transfer and variable adiabatic flame temperature is mainly responsible for NOx formation and other emissions. Hence fuel additives may play an important role to counteract such problems and achieve various specified standards. Researchers have used many additives to improve the quality of biodiesel such as metal-based additives, oxygenated additives, cetane improvers, ignition promoters, cold-flow improvers, antioxidants and lubricity improvers etc. This literature review characterizes the combustion behavior of diesel engines fuelled by diesel, biodiesel and its blends including additives. It was found that combustion characteristics were improved by introducing additives into diesel and biodiesel blends, while exhaust emissions are also reduced.H. K. Imdadul, H. H. Masjuki, M. A. Kalam, N. W. M. Zulkifli, M. M. Rashed, H. K. Rashedul, I. M. Monirul and M. H. Mosaro

Effect of Chemical Treatment on the Mechanical Properties of Luffa Fiber Reinforced Epoxy Composite

Novel luffa fiber reinforced epoxy composites are prepared and their mechanical properties are investigated before and after chemical treatment. The unique natural knitting structure of luffa provides an excellent reinforcement to the epoxy matrix. Knowing that the fiber-matrix bond gets stronger and imparts more strength to the composite when chemical treatment is done on fibers, composites are manufactured by untreated and treated luffa fiber using epoxy as a matrix. Luffa fiber is treated using benzoyl chloride and NaOH. Tensile and flexural tests are conducted on composites to investigate the effect of chemical treatment. Test results have shown that the chemical treatment on fibers improved the tensile strength, tensile modulus, flexural strength and flexural modulus by 27.21%, 49.37%, 41.84% and 6.44% respectively. Tensile modulus of luffa fiber composite is found to be higher compared with commonly used natural fiber composites. The experimental investigation suggests that, chemically treated luffa fiber reinforced epoxy composites could be a potential lightweight material in various applications.</jats:p

A comprehensive review on biodiesel cold flow properties and oxidation stability along with their improvement processes

Biodiesel, which comprises fatty acid esters, is derived from different sources, such as vegetable oils from palm, sunflower, soybean, canola, Jatropha, and cottonseed sources, animal fats, and waste cooking oil. Biodiesel is considered as an alternative fuel for diesel engines. However, biodiesel has poor cold flow behavior (i.e., high cloud point & pour point) and oxidation stability compared with petroleum diesel because of the presence of saturated and unsaturated fatty acid esters. Consequently, the performance of biodiesel during cold weather is affected. When biodiesel is oxidized, the subsequent dregs can adversely affect the performance of the fuel system as well as clog the fuel filter, fuel lines, and injector. This phenomenon results in start-up and operability problems. Cold flow behavior is usually assessed through the pour point (PP), cloud point (CP), and cold filter plugging point (CFPP). Earlier studies on cold flow focused on reducing the devastating effect of poor cold flow problems, such as lowering the PP, CP, and CFPP of biodiesel. This present paper provides an overview of the cold flow behavior and oxidation stability of biodiesel, as well as their effect on the engine operation system. The improvements on the behavior of cold flow of biodiesel are also discussed.I. M. Monirul, H. H. Masjuki, M. A. Kalam, N. W. M. Zulkifli, H. K. Rashedul, M. M. Rashed, H. K. Imdadul and M. H. Mosaro