85,980 research outputs found

    Time for Reform: Investing in Prevention: Keeping Children Safe at Home

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    Describes the prevention and reunification services needed in child welfare programs to reduce abuse and help families stay together. Recommends changes to the child welfare financing structure to allow states to lower the need for foster care

    In silico simulation of blood glucose-insulin dynamics using MATLAB-Simulink

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    Diabetes mellitus (DM) is a major public health concern in Malaysia and it continuously increases over years. Based on International Diabetes Federation, there are rising numbers of people having diabetes with 3.6 million people in Malaysia and 463 million people in the world [1]. The National Health and Morbidity Survey (NHMS) 2019 has shown that the diabetes in Malaysia has increased from 13.4% in 2015 to 18.3% in 2019 [2]. This can significantly increase the cost in diabetes treatment and management

    Removal of Boron from aqueous solutions by adsorption using fly ash, zeolite and demineralized lignite

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    In the present study for the purpose of removal of boron from water by adsorption using adsorbents like fly ash, natural zeolite and demineralized lignite was investigated. Boron in water was removed with fly ash, zeolite and demineralized lignite with different capacities. 94% boron was removed using fly ash. Batch experiments were conducted to test removal capacity, to obtain adsorption isotherms, thermodynamic and kinetic parameters. Boron removal by all adsorbents was affected by pH of solution; maximum adsorption was achieved at pH 10. Adsorption of boron on fly ash was investigated by Langmuir, Freundlich, Dubinin-Radushkevich models. Standard entropy and enthalpy changes of adsorption of boron on fly ash were, =S0 = -0.69 kJ/mol K and =H0 = -215.34 kJ/mol, respectively. The negative value of S0 indicated decreased randomness at the solid/solution interface during the adsorption boron on the fly ash sample. Negative values of H0 showed the exothermic nature of the process. The negative values of G0 implied that the adsorption of boron on fly ash samples was spontaneous. Adsorption of boron on fly ash occurred with a pseudo-second order kinetic model, intraparticle diffusion of boron species had also some effect in adsorption kinetics

    Determination of biosorption mechanism in biomass of agave, using spectroscopic and microscopic techniques for the purification of contaminated water

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    [Abstract] Lead (Pb2+) and copper (Cu2+) are polluting metals due to their toxicity; however, the extraction of these metals is essential for economic development, so it is important to look for efficient and low-cost alternatives that can remove heavy metals from the various bodies of water. One of the alternatives used in this work is biosorption, for which an agroindustrial waste (epidermis from Agave atrovirens) was used to evaluate the affinity of removal of lead and copper in aqueous solutions; in addition, spectroscopy and microscopy techniques were used to elucidate and corroborate the removal and affinity capacity of the agave epidermis for both metals studied. The optimal pH value for the removal of both metals was 3. The adsorption isotherms yielded a qmax of 25.7 and 8.6 mg/g for lead and copper, respectively. Adjusting to the Langmuir-Freundlich model, the adsorption kinetics were pseudo-second order, and it was found that the equilibrium time was at 140 min. The spectroscopy and microscopy analyses corroborated the affinity between metals and functional groups of the agave, as well as with the elemental analysis, which reported 17.38% of lead and 4.25% of copper.[Resumen] El plomo (Pb2+) y el cobre (Cu2+) son metales contaminantes debido a su toxicidad; sin embargo, la extracción de estos metales es indispensable para el desarrollo económico, por lo que es importante buscar alternativas eficientes y de bajo costo que puedan remover metales pesados de los diversos cuerpos de agua. Una de las alternativas utilizadas en este trabajo es la biosorción, para la cual se utilizó un residuo agroindustrial (epidermis de Agave atrovirens), para evaluar la afinidad de remoción del plomo y cobre en soluciones acuosas; adicionalmente, se emplearon técnicas de espesctroscopía y microscopía que permitieron elucidar y corroborar la capacidad de remoción y afinidad que tuvo la epidermis de A. atrovirens para ambos metales estudiados. El valor óptimo de pH para la remoción de ambos metales fue 3. Las isotermas de adsorción arrojaron una qmax de 25.7 y 8.6 mg/g para el plomo y cobre, respectivamente. Ajustando al modelo de Langmuir-Freundlich, las cinéticas de adsorción resultaron de pseudo-segundo orden, se encontró que el tiempo de equilibrio es a los 140 min. El análisis espectroscópico y microscópico, corroboró la afinidad entre metales y grupos funcionales del agave, así como con el análisis elemental, el cual reportó 17.38% de plomo y 4.25% de cobre

    Biowęgiel z pofermentacyjnej pozostałości kukurydzy hybrydowej - tani i wydajny sorbent metali ciężkich

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    Biochar produced from fermentation residue of maize hybrid was used in untreated form as a sorbent for the removal of Cd(II), Pb(II) and Zn(II) from aqueous solution. The capability of biochar to immobilized ions was investigated by leaching test. Equilibrium between biochar sample and studied elements in solution was reached at a contact time 30 min for Zn(II) and 90 min for Pb(II) and Cd(II). The experimental data were described by pseudofirst-order and pseudo-second-order kinetic model, two- and three-parameter isotherms in non-linear form. The maximum sorption capacity achieved was 30.07 mg.g(-1) in the case of Cd(II) ions, 99.44 mg.g(-1) in the case of Pb( II) and 40.18 in the case of Zn(II). Biochar developed for this study is comparable to conventional biochar, low cost, non-toxic and experimental results show that is a suitable and efficient sorbent for Cd(II), Pb(II) and Zn(II) removal from aqueous solutions.Web of Science26475774

    Spatial moment analysis of transport of nonlinearly absorbing pesticides using analytical approximations

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    Analytical approximations were derived for solute transport of pesticides subject to Freundlich sorption, and first-order degradation restricted to the liquid phase. Solute transport was based on the convection-dispersion equation (CDE) assuming steady flow. The center of mass (first spatial moment) was approximated both for a non-degraded solute pulse and for a pulse degraded in the liquid phase. The remaining mass (zeroth spatial moment) of a linearly sorbing solute degraded in the liquid phase was found to be a function of only the center of mass (first spatial moment) and the Damköhler number (i.e., the product of degradation rate coefficient and dispersivity divided by flow velocity). This relationship between the zeroth and first spatial moments was shown to apply to nonlinearly sorbing pulses as well. The mass fraction leached of a pesticide subject to Freundlich sorption and first-order degradation in the solution phase only was found to be a function of the Damköhler number and of the dispersivity, so independent of sorption. Hence perceptions of the effects of sorption on pesticide leaching should be reconsidered. These conclusions equally hold for other micropollutants that degrade in the solution phase onl

    Sorption of apolar pesticides by units of benzoic acid propyl ester in cyclic phosphazene

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    Indexación: Scopus.The effects of temperature, pH and agitation time (equilibrium) on the adsorption process of different pesticides on N3P3(OC6H4COOCH2CH2CH3)6 was studied. With optimal conditions experimental, the adsorption isotherms have been realized with through Langmuir and Freundlich models. Pesticides are compounds used mainly in agriculture to control various species (plants, insects, worms, fungi). Due to their physicochemical properties, they can remain for a long time in the application sites, bioaccumulating and moving between environmental compartments which generate various environmental problems. The results obtained showed a physisorption mechanism for the fve pesticides studied, with higher sorption for: azinphos methyl (93,5 mg kg-1), carbaryl (290.5 mg kg-1) and carbofuran (580.5 mg kg-1) at 20 ° C, according to the models used. © 2018 Sociedad Chilena de Quimica. All rights reserved.https://scielo.conicyt.cl/pdf/jcchems/v62n4/0717-9324-jcchems-62-04-3783.pd

    Perlaksanaan latihan industri dalam meningkatkan kebolehkerjaan : satu kajian kes pelajar-pelajar bidang perhotelan di Politeknik Johor Bahru

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    Kajian ini merupakan kajian penilaian perlaksanaan Latihan Industri dalam meningkatkan kebolehkeijaan pelajar-pelajar dalam kursus Pengurusan Hotel dan Katering. Kajian ini dilakukan untuk mengetahui sejauh mana pelajar dapat mengaplikasi ilmu teori dan praktikal semasa menjalani Latihan Industri. Selain daripada itu, kajian ini juga melihat sejauh mana Latihan Industri ini dapat meningkatkan kebolehkeijaan dari aspek kemahiran generik dan pengurusan perhotelan. Dalam pada itu, kajian ini juga melihat perbezaan antara pelajar lelaki dan perempuan dari kedua-dua aspek yang ditunjukkan. Kajian telah dijalankan di Politeknik Johor Bahru dalam Jabatan Hospitaliti dan menggunakan soal selidik sebagai data kuantitatif dan disokong oleh data kualitatif dari sesi temu bual semi berstruktur dalam memperolehi dapatan kajian. Seramai 147 sampel daripada 231 populasi yang disasarkan telah menjawab soal selidik yang dijalankan. Tiga orang pensyarah juga telah ditemu bual bagi menyokong dapatan kajian ini. Kesemua dapatan kajian telah dianalisis menggunakan SPPS versi 13.0. Dapatan kajian menunjukkan, pelajar-pelajar dapat mengaplikasi ilmu teori dan praktikal semasa menjalani Latihan Industri. Ini berdasarkan purata skor min yang ditunjukkan iaitu 3.74 dan 3.88. Kajian ini juga membuktikan, Latihan Industri dapat meningkatkan kebolehkeijaan dari aspek kemahiran generik dan pengurusan perhotelan dengan skor min mencapai tahap yang tinggi iaitu 4.08 dan 3.82. Selain daripada itu, tidak terdapat perbezaan yang signifikan antara pelajar lelaki dan perempuan dari aspek kemahiran generik. Berbeza pula dengan aspek pengurusan perhotelan di mana terdapat perbezaan yang signifikan antara pelajar lelaki dan perempuan

    Adsorption of uranium and thorium on new adsorbent prepared from Moroccan oil shale impregnated with phosphoric acid

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    Attention has been focused recently on the production of new adsorbents from Moroccan oil shale of Tarfaya (layer R3) by chemical activation with phosphoric acid and its application in wastewaters treatment. The optimal conditions for the preparation were searched and the tests of adsorption of uranium and thorium ions were affected. The best product was obtained by used of the ratio of activated agent/precursor equal 3 and activation of the mixture in air at 250°C during two hours after prepocessing at 120°C in air. Under these conditions the maximal adsorption capacity of methylene blue and specific area (SBET) of the new adsorbent were 526 mg/g and 630 m2/g, respectively. A batch mode experiment was used to explore the performances of this adsorbent for the removal of the U and Th from aqueous solutions prepared from UO2(NO3)2.6H2O and Th(NO3)4.5H2O. The adsorption parameters for the two radioelements were determined by application of the Langmuir, Freundlich and Elovich models
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