•This study adopted a holistic approach in investigating C&D waste generation.•The waste generation and composition data were compared with other countries.•The economic value of recycling will ...assist in managing the reuse programs.•The classified data of C&D waste is suggested an effective waste management plan.
Associated with the continuing increase of construction activities such as infrastructure projects, commercial buildings and housing programs, Bangladesh has been experiencing a rapid increase of construction and demolition (C&D) waste. Till now, the generation rate of C&D waste has not been well understood or not explicitly documented in Bangladesh. This study aims to provide an approach to estimate C&D waste generation using waste generation rates (WGR) through regression analysis. Furthermore, analyses the economic benefit of recycling C&D waste. The results revealed that WGR 63.74 kg/m2 and 1615 kg/m2 for construction and demolition activities respectively. Approximately, in financial year (FY) 2016, 1.28 million tons (0.149 construction and 1.139 demolition) waste were generated in Dhaka city, of which the three largest proportions were concrete (60%), brick/block (21%) and mortar (9%). After collection they were dumped in either landfills or unauthorized places. Therefore, it can be summarized as: waste is a resource in wrong place. The results of this study indicate that rapid urbanization of Dhaka city would likely experience the peak in the generation of C&D waste. This paper thus designates that C&D waste recycling is an entrepreneurial activity worth venturing into and an opportunity for extracting economic and environmental benefits from waste. The research findings also show that recycling of concrete and brick waste can add economic value of around 44.96 million USD. In addition, recycling of C&D waste leads to important reductions in CO2 emissions, energy use, natural resources and illegal landfills. Therefore, the findings of WGR and economic values provide valuable quantitative information for the future C&D waste management exercises of various stakeholders such as government, industry and academy.
We present cosmological results from a combined analysis of galaxy clustering and weak gravitational lensing, using 1321 deg2 of griz imaging data from the first year of the Dark Energy Survey (DES ...Y1). We combine three two-point functions: (i) the cosmic shear correlation function of 26 million source galaxies in four redshift bins, (ii) the galaxy angular autocorrelation function of 650,000 luminous red galaxies in five redshift bins, and (iii) the galaxy-shear cross-correlation of luminous red galaxy positions and source galaxy shears. To demonstrate the robustness of these results, we use independent pairs of galaxy shape, photometric-redshift estimation and validation, and likelihood analysis pipelines. To prevent confirmation bias, the bulk of the analysis was carried out while “blind” to the true results; we describe an extensive suite of systematics checks performed and passed during this blinded phase. The data are modeled in flat ΛCDM and wCDM cosmologies, marginalizing over 20 nuisance parameters, varying 6 (for ΛCDM) or 7 (for wCDM) cosmological parameters including the neutrino mass density and including the 457×457 element analytic covariance matrix. We find consistent cosmological results from these three two-point functions and from their combination obtain S8≡σ8(Ωm/0.3)0.5=0.773−0.020+0.026 and Ωm=0.267−0.017+0.030 for ΛCDM; for wCDM, we find S8=0.782−0.024+0.036, Ωm=0.284−0.030+0.033, and w=−0.82−0.20+0.21 at 68% C.L. The precision of these DES Y1 constraints rivals that from the Planck cosmic microwave background measurements, allowing a comparison of structure in the very early and late Universe on equal terms. Although the DES Y1 best-fit values for S8 and Ωm are lower than the central values from Planck for both ΛCDM and wCDM, the Bayes factor indicates that the DES Y1 and Planck data sets are consistent with each other in the context of ΛCDM. Combining DES Y1 with Planck, baryonic acoustic oscillation measurements from SDSS, 6dF, and BOSS and type Ia supernovae from the Joint Lightcurve Analysis data set, we derive very tight constraints on cosmological parameters: S8=0.802±0.012 and Ωm=0.298±0.007 in ΛCDM and w=−1.00−0.04+0.05 in wCDM. Upcoming Dark Energy Survey analyses will provide more stringent tests of the ΛCDM model and extensions such as a time-varying equation of state of dark energy or modified gravity.
A novel nano-adsorbent, carboxymethyl-β-cyclodextrin modified Fe
3O
4 nanoparticles (CMCD-MNPs) is fabricated for removal of copper ions from aqueous solution by grafting CM-β-CD onto the magnetite ...surface via carbodiimide method. The characteristics results of FTIR, TEM, TGA and XPS show that CM-β-CD is grafted onto Fe
3O
4 nanoparticles. The grafted CM-β-CD on the Fe
3O
4 nanoparticles contributes to an enhancement of the adsorption capacity because of the strong abilities of the multiple hydroxyl and carboxyl groups in CM-β-CD to adsorb metal ions. The adsorption of Cu
2+ onto CMCD-MNPs is found to be dependent on pH and temperature. Adsorption equilibrium is achieved in 30
min and the adsorption kinetics of Cu
2+ is found to follow a pseudo-second-order kinetic model. Equilibrium data for Cu
2+ adsorption are fitted well by Langmuir isotherm model. The maximum adsorption capacity for Cu
2+ ions is estimated to be 47.2
mg
/g at 25
°C. Furthermore, thermodynamic parameters reveal the feasibility, spontaneity and exothermic nature of the adsorption process. FTIR and XPS reveal that Cu
2+ adsorption onto CMCD-MNPs mainly involves the oxygen atoms in CM-β-CD to form surface-complexes. In addition, the copper ions can be desorbed from CMCD-MNPs by citric acid solution with 96.2% desorption efficiency and the CMCD-MNPs exhibit good recyclability.
We measure the clustering of DES year 1 galaxies that are intended to be combined with weak lensing samples in order to produce precise cosmological constraints from the joint analysis of large-scale ...structure and lensing correlations. Two-point correlation functions are measured for a sample of 6.6×105 luminous red galaxies selected using the redMaGiC algorithm over an area of 1321 square degrees, in the redshift range 0.15<z<0.9, split into five tomographic redshift bins. The sample has a mean redshift uncertainty of σz/(1+z)=0.017. We quantify and correct spurious correlations induced by spatially variable survey properties, testing their impact on the clustering measurements and covariance. We demonstrate the sample’s robustness by testing for stellar contamination, for potential biases that could arise from the systematic correction, and for the consistency between the two-point auto- and cross-correlation functions. We show that the corrections we apply have a significant impact on the resultant measurement of cosmological parameters, but that the results are robust against arbitrary choices in the correction method. We find the linear galaxy bias in each redshift bin in a fiducial cosmology to be b(σ8/0.81)|z=0.24=1.40±0.07, b(σ8/0.81)|z=0.38=1.60±0.05, b(σ8/0.81)|z=0.53=1.60±0.04 for galaxies with luminosities L/L*>0.5, b(σ8/0.81)|z=0.68=1.93±0.04 for L/L*>1 and b(σ8/0.81)|z=0.83=1.98±0.07 for L/L*>1.5, broadly consistent with expectations for the redshift and luminosity dependence of the bias of red galaxies. We show these measurements to be consistent with the linear bias obtained from tangential shear measurements.
This paper scrutinizes the fabrication of a chemiresistive type of acetylene (C2H2) gas sensor by synthesizing a silver (Ag)-loaded zinc oxide (ZnO)-reduced graphene oxide (Gr) hybrid via a facile ...chemical route. The as-synthesized hybrid was characterized in detail in terms of its structural, morphological and compositional properties. The physical properties of the hybrid exhibited a well-structured crystalline nature and mixed phases of Ag, Gr, and ZnO. The morphological characterization revealed that particle-like nanostructures of the ZnO and Ag mixer were well distributed and closely affixed onto the surface of thin-layer reduced graphene oxide sheets. At an optimum temperature of 150°C, the 3wt% Ag-loaded ZnO–Gr hybrid showed preferential detection of acetylene gas with a response value of 21.2 for 100ppm gas concentrations. The fabricated sensor showed a low detection limit of 1ppm, fast response and recovery times of 25s and 80s, respectively, and good repeatability. Experimental results also showed that the synthesized hybrid had a negligible relative humidity (RH) effect up to 31% RH, and then deteriorated significantly with increasing RH concentrations. After detailed examination, we conclude that an Ag-loaded ZnO–Gr hybrid could be an effective means of fabricating high-performance practical C2H2 sensors.
The current study aimed to qualitatively and quantitatively determine the phytochemical components of Cycas pectinata methanol extract (MECP), along with its antioxidant, anti-inflammatory, ...thrombolytic, locomotor, anxiolytic, analgesic, and antidiarrheal activities. The in vitro antioxidant activity was evaluated by DPPH scavenging assay and the total phenol and total flavonoid contents, while the anti-inflammatory activity was evaluated by a protein denaturation assay. The in vivo locomotor effects were examined using the open field test and hole-cross test. The anxiolytic effect was examined using the elevated plus maze (EPM) test, hole-board test (HBT), and light–dark test (LDT), while the analgesic activity was investigated using the acetic acid-induced writhing test. The antidiarrheal effect was evaluated by castor oil-induced diarrhea and gastrointestinal motility. Ten bioactive compounds were selected on the basis of their biological activities and further investigated using in silico molecular docking simulation to correlate with the identified pharmacological properties. Additionally, the ADME properties of the compounds were evaluated according to their drug-likeness profile. MECP had a maximum total phenol content of 209.85 ± 3.40 gallic acid equivalents/g extract and a total flavonoid content of 105.17 ± 3.45 quercetin equivalents/g extract, with an IC50 value of 631.44 μg/mL. MECP (62.5–500 μg/mL) elicited 20.96–38.12% decreased protein denaturation compared to diclofenac sodium (65.40–83.50%), while a 35.72% (P < 0.001) clot lysis activity was observed for the 10 mg/mL concentration. MECP induced a dose-dependent reduction in locomotor activity, with a significant anxiolytic effect. In the analgesic test, MECP (200, 400 mg/kg) showed a 45.12% and 58.82% inhibition in analgesia, and the 400 mg/kg dose elicited a 27.5% inhibition in intestinal motility. These findings suggest that MECP might be effective in treating antioxidant, anti-inflammatory, and neuropharmacological defects, but this requires further study.
Cycas pectinata; Antioxidant; Anxiolytic; Analgesic; Anti-inflammatory; Plant biology; Bioinformatics; Pharmaceutical science; Alternative medicine; Evidence-based medicine
This paper describes the synthesis of Pt/Pd bimetal decorated highly hydrophobic rough silicon nanowires (Si NWs) by using a facile metal assisted chemical etching and pulse laser deposition (PLD) ...process. In addition, the potential of the Si NWs as a new hydrogen (H2) detection matrix was investigated. The Pt/Pd bimetal was coated as a discrete ultra-thin film manner in a semi-dense configuration over the basal podium and along the length of vertical-standing and semi-densely distributed rough Si NW clusters. The resulting structure showed significant advantages in H2 sensing performances such as a large detection range of 1–40,000 ppm, high response magnitude of nearly 5.02%, and fast response-recovery time of 7/7 s to 10,000 ppm (1 vol%) hydrogen concentration at an optimum operating temperature of 75 °C. The observed characteristics of fast response-recovery time could relate to the enhanced hydrogen-induced changes in the work function of the Pt/Pd bimetal decorated Si NWs (Pt/Pd–Si NWs), which were configured as an array matrix comprising of many nanowire clusters with variable distances between the two electrodes. Finally, the fabricated sensor showed excellent repeatability towards (1 vol%) hydrogen concentration.
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•Hydrophobic Si nanowires synthesized by a metal assisted chemical etching process.•Quantum size (3/3 nm) Pt/Pd bimetal decorated on Si NWs by PLD method.•Feasibility of H2 sensing properties is investigated.•The mechanism for H2 response was described by diffusion pathway.
Herein we report an enhanced triboelectric nanogenerator (TENG) based on the contact-separation mode between a patterned film of polydimethylsiloxane (PDMS) with a semimetallic elastomer of ...poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and a nylon fiber film. The addition of ethylene glycol to the PEDOT:PSS film improves the functionality of the TENG significantly, yielding promising applicability in both indoor and outdoor (i.e., under sunlight) environments, with the maximum instantaneous power of 0.09 mW (indoors) and 0.2 mW (outdoors) for the load resistance of 3.8 MΩ. The device can also generate 11.2 V and 0.08 μA cm–2 in response to the forearm movement of a human. Additionally, by replacing the bare nylon fiber in the TENG design with a Ag@ZnO/nylon fiber film, a self-powered active sensor (triboelectric nanogenerator-based sensor; TENS) has been realized to detect acetylene (C2H2) gas. The TENS exhibits excellent sensitivity of 70.9% (indoors) and 89% (outdoors) to C2H2 gas of 1000 ppm concentration. The proposed approach for harvesting energy and sensing can be advantageous in practical applications and may stimulate new research that will enhance nanogenerators as well as wearable, self-powered active sensors.
Dietary supplements (DS) are products that improve the overall health and well-being of individuals and reduce the risk of disease. Evidence indicates a rising prevalence of the use of these products ...worldwide especially among the age group 18-23 years.
The study investigates the tendencies and attitudes of Bangladeshi undergraduate female students towards dietary supplements (DS).
A three-month (March 2018-May 2018) cross-sectional face-to-face survey was conducted in undergraduate female students in Chittagong, Bangladesh using a pre-validated dietary supplement questionnaire. The study was carried among the four private and three public university students of different disciplines in Chittagong to record their prevalent opinions and attitudes toward using DS. The results were documented and analyzed by SPSS version 22.0.
Ninety two percent (N = 925, 92.0%) of the respondents answered the survey questions. The prevalence of DS use was high in undergraduate female students. The respondents cited general health and well-being (n = 102, 11.0%) and physician recommendation (n = 101, 10.9%) as a reason for DS use. Majority of the students (n = 817, 88.3%) used DS cost monthly between USD 0.12 and USD 5.90. Most of the students (n = 749, 81.0%) agreed on the beneficial effect of DS and a significant portion (n = 493, 53.3%) recommended for a regular use of DS. Highly prevalent use of dietary supplements appeared in Chittagonian undergraduate female students. They were tremendously positive in using DS. The results demonstrate an increasing trend of using DS by the undergraduate females for both nutritional improvement and amelioration from diseases.
Dietary supplements prevalence was so much higher in students of private universities as compared to students of public universities. Likewise, maximal prevalence is indicated in pharmacy department compared to other departments. Students preferred brand products, had positive opinions and attitudes towards dietary supplements.
Skin barrier therapy during the neonatal period, when the skin barrier is most highly compromised and the risk of death is greatest, has been shown to have a number of potential benefits, including ...reduced risk of nosocomial sepsis. Topical application of emollients that augment skin barrier function was evaluated as a strategy for improving survival rates among hospitalized preterm infants in Bangladesh.
A prospective, randomized, controlled, clinical trial was conducted in the special care nursery at Dhaka Shishu (Children) Hospital, the largest tertiary care children's hospital in Bangladesh. Preterm infants (gestational age: < or = 33 weeks; N = 497) received daily topical applications of sunflower seed oil or Aquaphor ointment. Neonatal mortality rates were compared in an intent-to-treat analysis with a control group that did not receive emollient therapy.
Treatment with sunflower seed oil resulted in a statistically significant 26% reduction in mortality rates, compared with infants not receiving topical emollient therapy. Aquaphor therapy also significantly reduced mortality rates, by 32%.
Topical therapy with skin barrier-enhancing emollients improved survival rates among preterm hospitalized infants in Bangladesh. This study provides strong evidence for the implementation of topical therapy for high-risk preterm neonates in developing countries.
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