Application of Plant-Based Coagulants and Their Mechanisms in Water Treatment:A Review

This review describes the mechanisms of natural coagulants.It provides a good understanding of the two key processes of coagulation-flocculation:adsorption and charge neutralization,as well as adsorption and bridging.Various factors have influence the coagulation/flocculation process,including the effect of pH,coagulant dosage,coagulant type,temperature,initial turbidity,coagulation speed,flocculation speed,coagulation and flocculation time,settling time,colloidal particles,zeta potential,the effects of humic acids,and extraction density are explained.The bio-coagulants derived from plants are outlined.The impact of organic coagulants on water quality,focusing on their effects on the physicochemical parameters of water,heavy metals removal,and bacteriological water quality,is examined.The methods of extraction and purification of plant-based coagulants,highlighting techniques such as solvent extraction and ultrasonic extraction,are discussed.It also examines the parameters that influence these processes.The methods and principles of purification of coagulating agents,including dialysis,freeze-drying,ion exchange,electrophoresis,filtration,and centrifugation,are listed.Finally,it evaluates the sustainability of natural coagulants,focusing on the environmental,technical,and economic aspects of their use.At the end of this review,the readers should have a comprehensive understanding of the mechanisms,selection,extraction,purification,and sustainability of plant-based natural coagulants in water treatment.

Accounting Framework to Measure the Environmental Costs and Disclosed in Industrials Companies Case Study of Societe Cement Hamma Bouziane （SCHB） in Constantine

Accounting, being an integrated information system, is not merely influenced by its environment, but also affects environment as well, due to its crucial role in generating the necessary information to decision-makers. It has two main pillars： measuring and declaring the costs that result from the activities of companies, especially industrial companies because they affect the environment. Therefore, the objective of this research is to investigate how well industrial companies are committed to measuring their environmental duties and declaring them in their balance sheets. This topic will be developed over two parts： scientific basis of environmental costs and accounting; environmental measuring and disclosure.

Municipal Solid Waste Management in Constantine, Algeria

Constantine, with a population of 480,000 and containing 90,000 households, generated 164,250 tons of solid waste in 2015 in which domestic waste is the primary source. The aim of this study was to assess the situation of municipal solid-waste (MSW) management in Constantine. Actually, the collection and transportation of solid waste is managed by the municipality, with a small participation of the private sector. More than 90% of the municipality solid waste is disposed and treated in an environmentally sound manner (landfill). Unfortunately, there is a poor culture with respect to the 3R principles (reduce, reuse, recycle) in Constantine leading to a rapid growth of waste generation which has overwhelmed the capacity of the already saturated available landfill. There remain important challenges in solid waste management for the municipal authorities in Constantine which include: the proper management of the financial resources, public education aimed at reduction and separating household waste and optimizing the existing collection system.

Investigations on the Optimization of Contacts Barrier Height for the Improved Performance of ZnO/CdS/CZTS Solar Cells

The numerical simulations were performed using the AMPS-1D simulator to study the effects of the CZTS as an absorber layer and the contacts’barrier height on the performance of four ZnO/CdS/CZTS solar cells.To obtain the best cell performances,the barrier heights of the back and front contacts were adjusted between 0.01,0.77,0.5,and 1.55 eV,respectively.For simulations,we used the lifetime mode,and the device performances were evaluated under AM1.5 illumination spectra.We found that the efficiency,fill factor,and open-circuit voltage were almost constant at a front contact barrier height of less than 0.31 eV.The short-current density was not affected by the front contact barrier height.The back contact material had a significant impact on the CZTS cells parameters.The best performance was obtained for the CZTS550 cell with JSC=29.53 mA/cm2,VOC=1.07 V,FF=0.88,andη=28.08%at barrier heights of 0.31 and 1.55 eV for front and back contacts,respectively.The conduction band offset at the CZTS550/CdS hetero-junction was found to be spike-like with 0.21 eV.The obtained conversion efficiency is comparable to those previously reported in the literature.

Neural Network Based Adaptive Tracking Control for a Class of Pure Feedback Nonlinear Systems With Input Saturation

In this paper, an adaptive neural networks(NNs)tracking controller is proposed for a class of single-input/singleoutput(SISO) non-affine pure-feedback non-linear systems with input saturation. In the proposed approach, the original input saturated nonlinear system is augmented by a low pass filter.Then, new system states are introduced to implement states transformation of the augmented model. The resulting new model in affine Brunovsky form permits direct and simpler controller design by avoiding back-stepping technique and its complexity growing as done in existing methods in the literature.In controller design of the proposed approach, a state observer,based on the strictly positive real(SPR) theory, is introduced and designed to estimate the new system states, and only two neural networks are used to approximate the uncertain nonlinearities and compensate for the saturation nonlinearity of actuator. The proposed approach can not only provide a simple and effective way for construction of the controller in adaptive neural networks control of non-affine systems with input saturation, but also guarantee the tracking performance and the boundedness of all the signals in the closed-loop system. The stability of the control system is investigated by using the Lyapunov theory. Simulation examples are presented to show the effectiveness of the proposed controller.

Chemical analysis,antimicrobial and anti-oxidative properties of Daucus gracilis essential oil and its mechanism of action

Objective:To evaluate the essential oils(EO) composition,antimicrobial and antioxidant power of a local plant,Daucus gracilis(D.gracilis).Methods:The aerial parts of D.gracilis were subjected to hydro distillation by a Clevenger apparatus type to obtain the EO which had been analyzed by gas chromatography and gas chromatography coupled with mass spectrometry,and screened for antimicrobial activity against five bacteria and three fungi by agar diffusion method.The mechanism of action of the EO was determined on the susceptible strains by both of time kill assay and lysis experience.The minimal inhibitory concentrations were determined by agar macrodilution and micro-dilution methods.Anti-oxidative properties of the EO were also studied by free diphenyl-2-picrylhydrazyl radical scavenging and reducing power techniques.Results:The EO yielded 0.68(v/w).The chemical analysis presented two dominant constituents which were the elemicin(35.3%) and the geranyl acetate(26.8%).D.gracilis EO inhibited the growth of Bacillus cereus and Proteus mirabilis significantly with minimal inhibitory concentrations of 17.15 μg/mL by the agar dilution method and57.05 μg/mL and 114.1 μg/mL,respectively by liquid micro-dilution.A remarkable decrease in a survival rate as well as in the absorbance in 260 nm was recorded,which suggested that the cytoplasm membrane was one of the targets of the EO.The EO showed,also,important anti-oxidative effects with an IC50 of 0.002 mg/mL and a dosedependent reducing power.Conclusions:D.gracilis EO showed potent antimicrobial and anti-oxidative activities and had acted on the cytoplasm membrane.These activities could be exploited in the food industry for food preservation.

Stability of a Delayed SIQRS Model with Temporary Immunity

This paper addresses a time-delayed SIQRS model with a linear incidence rate. Immunity gained by experiencing the disease is temporary;whenever infected, the disease individuals will return to the susceptible class after a fixed period of time. First, the local and global stabilities of the infection-free equilibrium are analyzed, respectively. Second, the endemic equilibrium is formulated in terms of the incidence rate, and locally asymptotic stability. Finally we use the adomian decomposition method is applied to the system epidemiologic. This method yields an analytical solution in terms of convergent infinite power series.

Evaluation and Validation of Equivalent Five-Parameter Model Performance for Photovoltaic Panels Using Only Reference Data

This paper presents the modeling of electrical I-V verification of photovoltaic modules using five-parameter models based on the minimum usage of input data, which are usually provided by manufacturer’s datasheet. However, we vary them with a step of 10-4, the ideality factor between 0.0 and 4 for each iteration in order to choose the value, which gives a minimal relative error of the maximum power point. Moreover, when is known, the other four parameters (i.e., Rs, I0, Iph and Rsh) are known. Finally, the effectiveness of this approach is then validated through comparison of the experimental results data under outdoor weather conditions.

The Use of Aloe vera as Natural Coagulant in Algerian Drinking Water Treatment Plant

The purpose of this work is the study the ability of the plant material Aloe vera to act as natural coagulant using raw water obtained from a drinking water treatment plant(Mila,Algeria).Different solvents such as:NaCl;NaOH and HCl were used as chemical activators to extract the active components from the Aloe vera plant,and different coagulation-flocculation experiments were conducted in a jar test apparatus to evaluate the perfor-mance of the extracted coagulant.Also,the effect of coagulant dose on some water parameters such as turbidity,pH,total alkalinity and organic matter were investigated.The results showed that the use of coagulants obtained by using different solvents increases the coagulation efficiency compared to the coagulant obtained from the raw material,for example the maximum turbidity removal efficiency was 28.23,78.07,83.46 and 85.15%when using powdered Aloe vera(raw material),AV-NaCl(0.5 M),AV-NaOH(0.05 M)and AV-HCl(0.05 M),respectively.The results defined,that the residual turbidity obtained in this work,where the Aloe vera was used(after treat-ment by solvents)produced a turbidity lower than the Algerian standard(5 NTU)with initial turbidity(13 NTU).In this study,the infrared spectrum study and analysis has revealed the presence of different functional groups,which are responsible for the coagulation process.

Effect of TiO_2 and ZrO_2 reinforcements on properties of Al_2O_3 coatings fabricated by thermal flame spraying

The alumina composite coatings reinforced with 25% ZrO2 （denoted as AZ-25） and 3% TiO2 （denoted as AT-3） were deposited on low carbon steel using a thermal flame spraying. The microstructure, phase composition, microhardness and tribological properties of the coatings were investigated. The XRD results of the coatings reinforced by TiO2 （AT-3） revealed the presence of α-Al2O3 phase as matrix and new metastable phases of α-Al2O3 and α-Al2O3. However, the coatings reinforced by ZrO2 （AZ-25） consist of α-Al2O3 as matrix, q-ZrO2 and m-ZrO2. In most studied conditions, the AT-3 coating displays a better tribological performance, i.e., lower coefficient of frictions and wear rates, than the AZ-25 coating. It was also found that the microhardness of the coatings was decreased with the reinforcement of ZrO2 and increased with TiO2.

Structural and optical properties of a NaCl single crystal doped with CuO nanocrystals

A cupric oxide （CuO） nanocrystal-doped NaC1 single crystal and a pure NaCl single crystal are grown by using the Czochralski （Cz） method. A number of techniques, including X-ray diffraction （XRD）, scanning electron microscopy （SEM）, energy dispersive X-ray （EDX） analysis, Fourier transform infrared （FT-IR） spectroscopy, Raman spectroscopy, optical absorption in the UV-visible range, and photoluminescence （PL） spectroscopy are used to characterize the obtained NaCl and NaCI：CuO crystals. It is observed that the average radius of CuO crystallites in NaCI：CuO crystal is about 29.87 nm, as derived from the XRD data analysis. Moreover, FT-IR and Raman spectroscopy results confirm the existence of the monoclinic CuO phase in NaC1 crystal. UV-visible absorption measurements indicate that the band gap of the NaCI：CuO crystal is 434 nm （2.85 eV）, and it shows a significant amount of blue-shift （AEg = 1 eV ） in the band gap energy of CuO, which is due to the quantum confinement effect exerted by the CuO nanocrystals. The PL spectrum of the NaCI：CuO shows a broad emission band centred at around 438 rim, which is consistent with the absorption measurement.

Uses of Blast Furnace Slag as Complex Fertilizer

Significant quantities of slag are generated as waste material or by-product every day from steel industries. They usually contain considerable quantities of valuable metals and materials. Transforming these solid wastes from one form to another to be reused either by the same production unit or by different industrial installation is very much essential not only for conserving metals and mineral resources but also for protecting the environment. The sustainable development concept requires a more efficient management of waste materials and preservation of environment. The paper presents the basic characteristics of slag, analyses and it＇s modification by incorporating some essential plant nutrients and the possibility of its application as fertilizer was studied.

Influence of heat treatment on microstructure and tribological properties of flame spraying Fe–Ni–Al alloy coating

The Fe-based coatings in powder form were deposited on a steel type E335 by flame spraying technique.The effects of the post heat treatment on the microstructure and the mechanical properties of sprayed coatings were studied.Post heat treatment was conducted in a furnace in air at 623 K,823 K and 1023 K for 1 h and then cooled in air.The results showed that with the increase of annealing temperature,the microstructure of coating treated at 823 K and 1023 K had several changes as follows:the reduction of porosity,formation of carbides and oxides.It was found that the solid solution FCC(Fe,Ni),intermetallic compound AlFe3 and carbides[Fe,C]were the main phases for coatings as-sprayed and treated at 623 K and while iron carbide,molybdenum carbide and oxide as Fe3O4 became the main phases and reinforced the solid solution FCC(Fe,Ni)phase for annealed coatings at 823 K.However,it was observed the disappearance of molybdenum carbide and oxide Fe3O4 at 1023 K.The coating annealed at 823 K exhibited an excellent wear resistance than the as-sprayed and annealed coatings at 623 K and 1023 K and shows the lower wear rate than another coating treated or as sprayed.

Solubility of Solids in Supercritical Fluids: The Mendez-Santiago Teja Model Revisited

For the development and enhancement of supercritical applications, it is crucial to know the solubility of the considered compound in the supercritical fluid (SCF) in order to determine the conditions to achieve the best outcome. Many models have been developed to calculate supercritical solubility behavior and most can be either a semi empirical relationship or based on an equation of state. The Mendez-Santiago and Teja (MST) model is one of the most semiempirical models used. In this work, a review of the (MST) model from an accuracy and ability viewpoint is accomplished to give concise discussion and so to the proposition of a modification.

Denitrification in Natural Nutritious Medium

The intensive use of nitrogen fertilizers in Algeria caused a pollution of the waters by nitrates. This concentration reached in the region of Collo （Wilaya of Skikda, Algeria） 570 mg/L, which is beyond the WHO standard （50 mg/L）. This has negative consequences on human health （Methemoglobinemia） and on the environment （eutrophication）. In our works, we studied the elimination of this pollution with the use of a mixed culture of microorganisms. We replaced the standard synthetic carbon source and the nutritious medium by date powder. This contains minerals and sugars that can enhance bacterial growth. Our study showed that the effectiveness of denitrification is proportional to bacterial growth. It rises exponentially after a latency period of 8 hours. During the reaction of degradation we noticed a rise in pH in our engine, it moved from 7.00 to 8.38. In studying the influence of initial pH on the denitrification of the microorganisms, we observed that the ion hydrogen concentration modified the growth rate of bacteria and degradation of nitrates. An acid pH, the reduction of nitrates is incomplete; this is accounted for the accumulation of nitrous and nitric oxide that interferes in the reaction of denitrification. The velocity of the nitrate reduction is less important in an acid pH （0.0096 g.L^-l.h^-1） than in a basic pH （0.013 g.L^-1.h^-1）. The denitrification is optimal at temperature 35 ℃ for a ratio C/N = 2.5. In these conditions 95% of the nitrate initial quantity is eliminated after approximately 100 hour treatment.

Recovery and Use of Blast Furnace Slag in the Field of Road Construction in Algeria

Waste and industrial by-products represent a significant percentage of the industrial landfill. The evaluation of these products has a dual effect: it avoids both the landfill (risk of environmental pollution) and limits the use of natural aggregates (depletion of natural resources and landscape fragmentation and the imbalance of the ecosystem). In recent years, applications for industrial waste have been taken into account in the construction of roads with a great interest in many industrialized countries and developing countries. The use of these materials in the construction of the road is a decision based on technical, economic and ecological criteria. In Algeria, the steel plant of El-Hadjar (Annaba), due to its activity generates a significant industrial waste (slag) which creates a storage problem and pollution. For industrialized countries, this product is an abundant raw material at low cost that must be used on a large scale public works. Our study implies the use of slag in the preparation of the subgrade and surface course (as coated). The results of chemical, physical and mechanical analyses of El-Hadjar slag and materials developed, compared to those of natural aggregates, can be used as aggregate in road construction.

Effect of Substrates on the Properties of ZnO Thin Films Grown by Pulsed Laser Deposition

Polycrystalline zinc oxide (ZnO) thin films have been deposited at 450°C onto glass and silicon substrates by pulsed laser deposition technique (PLD). The used source was a KrF excimer laser (248 nm, 25 ns, 5 Hz, 2 J/cm2). The effects of glass and silicon substrates on structural and optical properties of ZnO films have been investigated. X-ray diffraction patterns showed that ZnO films are polycrystalline with a hexagonal wurtzite—type structure with a strong (103) orientation and have a good crystallinity on monocrystalline Si(100) substrate. The thickness and compositional depth profile were studied by Rutherford Backscattering spectrometry (RBS). The average transmittance of ZnO films deposited on glass substrate in the visible range is 70%.

Impact of the Built Environment on the Mental Health of the Inhabitants in High-Rise Collective Housing in Algeria

For everybody, the house or the accommodation （and its environment） is a secure place, a haven space, which protects people from constraints of the everyday life. Unfortunately, and more or less everywhere in the third world, accommodation is for a great number of people a source of stress caused by daily obligations that people have to deal with. In Algeria, the majority of the high-rise collective housing estates through the country offers all the ingredients of a constrained urban environment for the inhabitants. For the most of the population, the accommodation appears as a vital need rather than a negotiable good. As a matter of fact, in the third world in general and particularly in Algeria, most of people live in communities where there is a shortage of accommodation and in which the social housing and its environment are often below the standards. Constructed on policies and a conception of housing which does not integrate at all the criteria of the sustainable development, millions of fiats have already been built. Millions are going to be built in the future, and will be of high-rise collective type. As underlined in this paper, it seems reasonable to think that such a degraded built environment will be unfavorable to the inhabitants and will have a negative impact on both their mental and physical health. The attempt is to demonstrate that there are evidences according to which the housing conditions, inside and outside the accommodation, contribute to create psychological distress and physiological diseases.

Chemical composition and antibacterial activity of essential oil of Launaea lanifera Pau grown in Algerian arid steppes

Objective: To evaluate the essential oil composition and the antibacterial activity of an Algerian endemic plant, Launaea lanifera Pau(L. lanifera), grown in arid steppe regions.Methods: L. lanifera essential oil was isolated from aerial parts by steam distillation and its chemical composition was evaluated by gas chromatographyflame ionization detector and gas chromatography with electron impact mass spectrometry. Furthermore, its in vitro antibacterial activity against four bacterial strains was tested following the agar disk diffusion method.Results: This species had a very low essential oil yield(0.005%). Twenty-four(92.6%)individual components were identified. The main constituents were hexahydrofarnesyl acetone(31.6%),(E)-b-ionone(8.5%),(E)-b-damascenone(7.0%), 2-methyltetradecane(3.8%), n-heptadecane(3.8%), limonene(2.8%) and b-caryophyllene(2.8%). No noteworthy antimicrobial activity was observed on the tested bacteria, neither Gram negative nor Gram positive.Conclusions: This is the first report on the volatile constituents and antibacterial activity of L. lanifera. The studied essential oil does not possess significant activity against the tested microorganisms.