Groundwater Drought in the Northwestern Districts of Bangladesh

Prolonged absence of groundwater within the operating range of shallow tube-wells during dry season is a common problem in the northwestern districts of Bangladesh in the recent years. In this paper, groundwater scarcity and drought in three northwestern districts of Bangladesh have been investigated. The Cumulative Deficit approach from a threshold groundwater level has been used for the computation of severity of groundwater droughts. Monthly groundwater fluctuation data collected from 85 sites is used for the study. The study shows that groundwater scarcity in 42% area is an every year phenomenon in the region. Analysis of groundwater hydrographs and rainfall time-series reveals that ever increasing groundwater extraction for irrigation in the dry season and recurrent droughts are the causes of groundwater level drop in the region.     

Perfluorinated Alkyl Acids in Blood Serum from Primiparous Women in Sweden: Serial Sampling during Pregnancy and Nursing, And Temporal Trends 1996-2010

We investigated temporal trends of blood serum levels of 13 perfluorinated alkyl acids (PFAAs) and perfluorooctane sulfonamide (FOSA) in primiparous women (N = 413) from Uppsala County, Sweden, sampled 3 weeks after delivery 1996-2010. Levels of the short-chain perfluorobutane sulfonate (PFBS) and perfluorohexane sulfonate (PFHxS) increased 11%/y and 8.3%/y, respectively, and levels of the long-chain perfluorononanoate (PFNA) and perfluorodecanoate (PFDA) increased 4.3%/y and 3.8%/y, respectively. Concomitantly, levels of FOSA (22%/y), perfluorooctane sulfonate (PFOS, 8.4%/y), perfluorodecane sulfonate (PFDS, 10%/y), and perfluorooctanoate (PFOA, 3.1%/y) decreased. Thus, one or several sources of exposure to the latter compounds have been reduced or eliminated, whereas exposure to the former compounds has recently increased. We explored if maternal levels of PFOS, PFOA, and PFNA during the early nursing period are representative for the fetal development period, using serial maternal serum samples, including cord blood (N = 19). PFAA levels in maternal serum sampled during pregnancy and the nursing period as well as in cord blood were strongly correlated. Strongest correlations between cord blood levels and maternal levels were observed for maternal serum sampled shortly before or after the delivery (r = 0.70-0.89 for PFOS and PFOA). A similar pattern was observed for PFNA, although the correlations were less strong due to levels close to the method detection limit in cord blood.     

Sorption potential of rice husk for the removal of 2,4-dichlorophenol from aqueous solutions: kinetic and thermodynamic investigations

The sorption potential of chemically and thermally treated rice husk (RHT) for the removal of 2,4-dichlorophenol (DCP) from aqueous solutions has been investigated. Sorption of DCP by rice husk was observed over a wide pH range of 1-10. The effect of contact time between liquid and solid phases, sorbent dose, pH, concentration of sorbate and temperature on the sorption of DCP onto rice husk has been studied. The pore area and average pore diameter of RHT by BET method are calculated to be 17+/-0.6 m2g-1 and 51.3+/-1.5 nm, respectively. Maximum sorption (98+/-1.2%) was achieved for RHT from 6.1x10(-5) moldm(-3) of sorbate solution using 0.1g of rice husk for 10 min agitation time at pH 6 and 303K, which is comparable to activated carbon commercial (ACC) 96.6+/-1.2%, but significantly higher than chemically treated rice husk (RHCT) 65+/-1.6% and rice husk untreated (RHUT) 41+/-2.3%. The sorption data obtained at optimized conditions was subjected to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherms. Sorption intensity 1/n (0.31+/-0.01) and sorption capacity multilayer C(m) (12.0+/-1.6 mmolg(-1)) have been evaluated using Freundlich sorption isotherm, whereas the values of sorption capacity monolayer Q (0.96+/-0.03 mmolg(-1)) and binding energy, b, (4.5+/-1.0)x10(4)dm(3)mol(-1) have been estimated by Langmuir isotherm. The Langmuir constant, b, was also used to calculate the dimensionless factor, R(L), in the concentration range (0.6-6.1)x10(-4) moldm(-3), suggesting greater sorption at low concentration. D-R sorption isotherm was employed to calculate sorption capacity X(m) (2.5+/-0.07 mmolg(-1)) and sorption energy E (14.7+/-0.13 kJmol(-1)). Lagergren and Morris-Weber equations were employed to study kinetics of sorption process using 0.2g of RHT, 25 cm(3) of 0.61x10(-4)moldm(-3) sorbate concentration at pH 6, giving values of first-order rate constant, k, and rate constant of intraparticle transport, R(id), (0.48+/-0.04 min(-1) and 6.8+/-0.8 nmolg(-1)min(-1/2), respectively) at 0.61x10(-4)moldm(-3) solution concentration of DCP, 0.1g RHT, pH 6 and 2-10min of agitation time. For thermodynamic studies, sorption potential was examined over temperature range 283-323 K by employing 6.1x10(-4)moldm(-3) solution concentration of DCP, 0.1g RHT at pH 6 and 10 min of agitation time and values of DeltaH (-25+/-1 kJmol(-1)), DeltaS (-61+/-4 Jmol(-1)K(-1)) and DeltaG(303K) (-7.1+/-0.09 kJmol(-1)) were computed. The negative values of enthalpy, entropy, and free energy suggest that the sorption is exothermic, stable, and spontaneous in nature.     

Cleavage Strength of Steel/Composite Joints

This paper presents the experimental results of an on-going study to examine cleavage strength, particularly at the interface regions of epoxy adhesive with steel and glass reinforced epoxy (GRE) composite. The adhesion is characterised by mechanical testing of cleavage specimens. A standard specimen was modified to allow testing of hybrid joints. The effects of adhesive thickness and various surface conditions of both adherends were examined. Among key conclusions, the study found that cleavage strength is not strongly dependent upon adhesive thickness and that polished composite gives better adhesion compared with polished steel. Test results were analysed and compared with aspects of numerical analyses. The study has also established a new methodology to test hybrid adhesive cleavage joints.     

Effect of the Nanoparticle Exposures on the Tomato Bacterial Wilt Disease Control by Modulating the Rhizosphere Bacterial Community

Ralstonia Solanacearum is one of the most infectious soil-borne bacterial plant pathogens, causing tomato bacterial wilt (TBW). Nanotechnology is an emerging area of research, particularly the application of nanoparticles (NPs) as nanopesticides to manage plant disease is gaining attention nowadays. However, the interaction between NPs and rhizosphere bacterial communities remains largely elusive. This study indicated that metal NPs (CuO, ZnO, and FeO) reduced the incidence of bacterial wilt to varying degrees and affected the composition and structure of the rhizosphere bacterial community. The results revealed that the application of metal oxide NPs can improve the morphological and physiological parameters of TBW infected tomato plants. Among all, CuONPs amendments significantly increase the Chao1 and Shannon index. In the early stage (the second week), it significantly reduces the relative abundance of pathogens. However, the relative abundance of beneficial Streptomyces bacteria increased significantly, negatively correlated with the relative abundance of pathogenic bacteria. In addition, the nano-treatment group will enrich some potential beneficial bacteria such as species from Sphingomonadaceae, Rhizobiaceae, etc. In general, our research provides evidence and strategies for preventing and controlling soil-borne disease tomato bacterial wilt with metal oxide NPs.     

Energy-efficient sender-initiated threshold-based load balancing (e-STLB) in cloud computing environment

Cloud computing has transformed service delivery through its pay-per-use model, supporting diverse users with multiple heterogeneous Virtual Machines (VMs). However, energy consumption has emerged as a critical concern, necessitating cloud resource optimization for environment-friendly practices. This research paper presents an innovative energy-efficient threshold-based sender-initiated load-balancing strategy (e-STLB) to address this concern. The approach employs threshold values to trigger task migration between VMs, ensuring optimal performance while maximizing energy efficiency. The proposed strategy significantly reduces Makespan and increases Resource Utilization in an energy-conscious manner. Experimental evaluations using Cloudsim 3.0 demonstrate that the e-STLB outperforms other state-of-the-art solutions, offering a compelling approach to sustainable cloud computing.     

Methane and oxygen from energy-efficient,low temperature in situ resource utilization enables missions to Mars

The United States National Aeronautics and Space Administration's (NASA's) mandate is a human mission to Mars in the 2030s and sustained exploration of Mars requires in situ resource utilization (ISRU). Exploiting the Martian water cycle (alongside perchlorate salts that depress water's freezing point to <213 K) and the available 95 vol.% atmospheric CO₂, we detail an ultra-low temperature (255 K) CO₂–H₂O electrolyzer to produce methane fuel and life-supporting oxygen on Mars. Our polarization model fit experimental Martian brine electrolyzer performance and predicted CO₂ electrolysis occurring at comparatively lower potentials (vs. water electrolysis) on Mars. A hypothetical 10-cell, 100 cm² electrode-area-per-cell electrolyzer produced 0.45 g W⁻¹ day⁻¹ of CH₄ and 3.55 g W⁻¹ day⁻¹ of O₂ at 2 V/cell and 50% electrolyzer faradaic efficiency versus a best-case production of 2.5 g W⁻¹ day⁻¹ of O₂ by the Mars Oxygen in situ Resource Utilization Experiment (MOXIE) from NASA's Mars 2020 mission (MOXIE produces no fuel). Material performance requirements are presented to advance this technology as an energy-efficient complement to MOXIE.     

Effects of Fluid Properties on Rod Seal Stick-Slip Mechanical and Sound Vibrations

The effect of fluid properties on hydraulic cylinder rod seal stick-slip friction was studied. Breakaway and stick-slip forces were measured for three ISO VG 32 fluids with slipper, U-cup, and Vee-pack seals. Breakaway forces increased exponentially with dwell time. Stick-slip friction produced audible low-frequency noise. Differences in the stick-slip behavior of the fluids were observed. Fast Fourier transform analysis of sound, force, and mechanical vibrations was conducted. Stick-slip friction increased the amplitude of low-frequency vibrations in all three domains. Micro stick-slip movement was elucidated via motion amplification technology. These findings provide a basis for the development of fluids that improve the control and safety of hydraulic equipment.     

A novel hybrid requirement’s prioritization approach based on critical software project factors

Cognition, Technology & Work - Requirements prioritization is essential for development of quality software products. Requirements prioritization helps focus on the most important requirements...