357 research outputs found

    Removal of mercury (II) from aqueous solution by using rice residues

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    Sorption potential of rice residues for Hg(II) removal from aqueous solution was investigated. Rice husk (RH) and rice straw (RS) were selected and treated with sodium hydroxide (NaOH). The raw and modified adsorbents were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and BET surface area measurements. The effects of pH, initial ion concentration, and agitation time on the removal process were studied in batch adsorption experiments. Two simple kinetic models, which are pseudo-first-order and pseudo-second-order, were tested to investigate the adsorption mechanisms. The kinetic data fits to pseudo second order model with correlation coefficients greater than 0.99 for all adsorbents. The equilibrium data fitted well with the Langmuir compared to Freundlich isotherm models. Alkali-treated adsorbent obtained larger surface area and RH-NaOH showed highest adsorption capacity followed by RS-Pure > RH-Pure > RS-NaOH. The maximum removal efficiency obtained by RH-NaOH and RS-Pure was 42 mg/l (80%) at pH 6.5 and with 2 days contact time (for 50 mg/l initial concentration and 25 mg adsorbents)

    Pemetaan Mikrozonasi Seismik di Desa Nunkurus Kecamatan Kupang Timur Kabupaten Kupang

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     Telah dilakukan penelitian mikrozonasi seismik di desa Nunkurus Kecamatan Kupang Timur Kabupaten Kupang. Penelitian ini bertujuan untuk mengetahui  nilai frekuensi dominan tanah, nilai ampifikasi, indeks kerentanan tanah dan percepatan tanah serta membuat peta indeks kerentanan tanah dan peta. Berdasarkan hasil penelitian diperoleh nilai frekuensi dominan tanah berkisar antara 0.293 Hz – 18.41 Hz, nilai amplifikasi berkisar antara 1,68–8,52, nilai indeks kerentanan seismik  berkisar antara 0,3285 –179,23556 dan nilai PGA berkisar antara 107,77488 gal-218,62941 gal sehingga dapat dikatakan bahwa daerah penelitian berada dalam kawasan yang cukup aman karena hanya sebagian titik saja yang memiliki nilai frekuensi, nilai amplifikasi, nilai indeks kerentanan dan nilai PGA yang besar. Kata kunci : Mikrozonasi, HVSR, Nunkurus &nbsp

    Improving newborn health in countries exposed to political violence: an assessment of the availability, accessibility, and distribution of neonatal health services at Palestinian hospitals

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    Introduction: Geopolitical segregation of Palestine has left a fragile healthcare system with an unequal distribution of services. Data from the Gaza Strip reflect an increase in infant mortality that coincided with a significant increase in neonatal mortality (12.0 to 20.3 per 1,000 live births). Objective: A baseline study was carried out to evaluate available resources in neonatal units throughout Palestine. Study Design: A cross-sectional, hospital-based study was conducted in 2017 using the World Health Organization's "Hospital care for mothers and newborn babies: quality assessment and improvement tool." Data on the main indicators were updated in 2018. Results: There were 38 neonatal units in Palestine: 27 in the West Bank, 3 in East Jerusalem, and 8 in the Gaza Strip. There was an uneven geographic distribution of incubators in relation to population and births that was more marked in the Gaza Strip; 79% of neonatal units and 75% of incubators were in the West Bank. While almost all hospitals with neonatal units accepted very and extremely low birth weight and admitted out-born neonatal cases, there was a shortage in the availability of incubators with humidifiers, high-frequency oscillatory ventilation, mechanical ventilators with humidifiers and isolation wards. There was also a considerable shortage in neonatologists, neonatal nurses, and pediatric subspecialties. Conclusion: Almost all the neonatal units accepted extremely low birth weight neonatal cases despite not being ready to receive these newborns due to considerable shortages in human resources, equipment, drugs, and essential blood tests, as well as frequent disruptions in the availability of based amenities. Together, these factors contribute to the burden of providing quality care to newborns, which is further exacerbated by the lack of referral guidelines and challenges to timely referrals resulting from Israeli measures. Ultimately, this contributes to suboptimal care for neonates and negatively impacts future health outcomes

    ETIOLOGY OF FUNGI ASSOCIATED WITH GRAPEVINE DECLINE AND THEIR PATHOLOGICAL POTENTIAL

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    Decline of grapevine due to soil borne fungi was surveyed during 2013- 2015 summer growing seasons at El-Fayoum, El-Gharbeia and El-Beheira governorates, Egypt, Syndromes of declined grapevine plants included growth retardant of shoot system and root-rot as well as decrease of grapevine fruit yield  quality. Isolation trails from root of declined trees of different grapevine cultivars i.e., superior, flame seedless, King robi and crimson was carried out. The most soil borne fungi associated with root-rotted grapevine were Fusarium oxysporum Schlechtend, Fusarium solani (Mart.) Sacc, Botryodiplodia theobromae, Rhizoctonia solaniKuhn and Macrophomina phaseolina(Tassi) Gold. Fusarium spp. are the main fungal associated with different infection types of declined root of grapevine either a singly or in combination with B. theobromae or R. solani as second infection type and third infection type with B. theobromae + R. solani. Under soil artificially infested with 5% (w/w) of each fungal isolates inocula of fourteen isolates obtained were varied for causing wilt and root-rot symptoms of grapevine trees and reducing growth parameters plant height, root length, root size, fresh and dry weight of shoot and root than the control. Botrydiplodia theobromae isolate No. (7)was the most caused root-rot and disease severity of shoot and root of grapevine plant(100%)  followed by Fusarium avenacum caused (87.5%) of root –rot and disease severity of shoot and root. Fouthermore, Fusarium avenacum isolate was the most fungal isolate in reducing growth parameters expect root length.  This is first record that Fusarium avenacum as a causal organism causing root rot disease of grapevine in Egypt

    Performance of nano metaclay on chloride diffusion for ultra- high performance concrete

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    The major cause for corrosion of steel reinforcement embedded in concrete due to chloride penetration has been the great research effort. The use of nano metaclay in UHPC increase the strength and helps the formation of micro pores by acting as a filler thus improve the chloride penetration resistance characteristic. The aim of this study is to evaluate the chloride diffusion of UHPC using RCPT and chloride penetration depth. Four (4) series of UHPC comprised of plain UHPC and a series of nanoUHPC incorporating 1%, 3% and 5% of nano metaclay were produced. It is reported that the compressive strength of nano UHPCl exhibits higher strength up to 10% compared to plain UHPC. The results showed that UHPC containing nano metaclay also significantly affect the chloride diffusion coefficient. As regards to the results, inclusion of 1% nano metaclay in UHPC led to noticeable benefit towards strength and chloride resistance

    B-site vacancy induced Raman scattering in BaTiO3-based ferroelectric ceramics

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    Defects, in particular vacancies, play a crucial role in substituted perovskite systems, influencing the structural features that underpin ferroelectricity. B-site vacancies introduce cation disorder in the perovskite lattice and are in fact one of the main driving forces for relaxor behaviour in barium titanate (BaTiO3, BT) based ferroelectrics. In this work, material systems are carefully selected to qualitatively study the change in B-site vacancy concentration for heterovalent substituted BT-based ferroelectric polycrystals. Raman spectroscopy was used to investigate those systems, and B-site vacancy specific Raman modes were identified unambiguously by comparison with charge-compensated BT, where B-site vacancies are absent. This study validates the hypothesis that vacancies induce Raman scattering because of symmetry breaking in the BT lattice, establishing this method as a vital tool to study substitutional defects in ceramic materials

    Cetyltrimethylammonium bromide-coated agrosorbents and their high benzene adsorption performance from aqueous solution

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    Cetyltrimethylammonium bromide-coated agrosorbents were successfully synthesized through firstly mercerization of raw banana trunk (Raw-BT) with alkali (M-BT) and finally coating with cetyltrimethylammonium bromide (M-CTAB-BT). The characterization was done using an energy dispersive X-ray spectrophotometer, a Fourier transform infrared spectrophotometer and a field emission scanning electron microscope. The Brunauer, Emmett, and Teller analysis was also conducted. The benzene adsorption performance of BT agrosorbents was improved by mercerization and surfactant coating according to the following order: Raw-BT (340.25 × 10−mmol/g) < CTAB-BT (382.41 × 10−3 mmol/g) < M-CTAB-BT (535.62 × 10−3mmol/g). The adsorption data obeyed the Langmuir and pseudo-second order (PSO) kinetic models with film diffusion as the rate-limiting step. The agrosorbent regeneration as well as comparison to literature data indicated the modified BT and thus the agrowaste biomass could be alternative agrosorbent precursors for removing benzene from aqueous solutions. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 305–317, 2018
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