Search results for: green chemical analysis

Authors: Yuri S. Djikaev

Abstract:

A large subset of aqueous aerosols can be initially (immediately upon formation) coated with various organic amphiphilic compounds whereof the hydrophilic moieties are attached to the aqueous aerosol core while the hydrophobic moieties are exposed to the air thus forming a hydrophobic coating thereupon. We study the thermodynamics of water condensation on such an aerosol whereof the hydrophobic organic coating is being concomitantly processed by chemical reactions with atmospheric reactive species. Such processing (chemical aging) enables the initially inert aerosol to serve as a nucleating center for water condensation. The most probable pathway of such aging involves atmospheric hydroxyl radicals that abstract hydrogen atoms from hydrophobic moieties of surface organics (first step), the resulting radicals being quickly oxidized by ubiquitous atmospheric oxygen molecules to produce surface-bound peroxyl radicals (second step). Taking these two reactions into account, we derive an expression for the free energy of formation of an aqueous droplet on an organic-coated aerosol. The model is illustrated by numerical calculations. The results suggest that the formation of aqueous cloud droplets on such aerosols is most likely to occur via Kohler activation rather than via nucleation. The model allows one to determine the threshold parameters necessary for their Kohler activation. Numerical results also corroborate previous suggestions that one can neglect some details of aerosol chemical composition in investigating aerosol effects on climate.

Keywords: aqueous aerosols, organic coating, chemical aging, cloud condensation nuclei, Kohler activation, cloud droplets

Procedia PDF Downloads 379

Authors: Bilal Jabakhanji, Dimitris Kazazis, Adrien Michon, Christophe Consejo, Wilfried Desrat, Benoit Jouault

Abstract:

In this paper, we investigate the electrical properties of graphene grown by Chemical Vapor Deposition (CVD) on the Si face of SiC substrates. Depending on the growth condition, hole or electron doping can be achieved, down to a few 1011cm−2. The high homogeneity of the graphene and the low intrinsic carrier concentration, allow the remarkable observation of the Half Integer Quantum Hall Effect, typical of graphene, at the centimeter scale.

Keywords: graphene, quantum hall effect, chemical vapor, deposition, silicon carbide

Procedia PDF Downloads 649

Authors: Manal M. Hamed, Mosad A. Ghareeb, Abdel-Aleem H. Abdel-Aleem, Amal M. Saad, Mohamed S. Abdel-Aziz, Asmaa H. Hadad

Abstract:

Natural products derived from medicinal plants provide unlimited opportunities for a new medication leads because of the unmatched accessibility of chemical variation. Six compounds were isolated from the n-butanol extract of Callistemon citrinus (Family Myrtaceae), they were identified as; nepetolide (1), callislignan A (2), 6,8-dimethoxy-4,5-dimethyl-3-methyleneisochroman-1-one (3), 3-methyl-7-O-benzoyl-β-D-glucopyranoside (4), 5, 7, 3', 5'-tetrahydroxy-6, 8-di-C-methyl flavanone (5), and (2R,3R,4S,5S)-2,4-bis(4-hydroxyphenyl)-3,5-dihydroxy-tetrahydropyran (6). The isolated compounds were evaluated as antioxidant and antimicrobial agents. The antioxidant activities of the compounds were determined using DPPH-radical scavenging and total antioxidant capacity (TAC) assays. The results indicated that compound (5) was most active in its capacity to scavenge free radicals in the DPPH assay [SC50 value, 4.65 ± 0.74μg/mL] compared to the standard ascorbic acid and exhibited the highest activity in the TAC assay (610.45 ± 1.67mg AAE/g compound). The pure isolates were tested for their antimicrobial activity against four pathogenic microbial strains including Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Candida albicans. Also, the GC/MS analysis of its leaves essential oil presented nine identified compounds representing 91% of the total oil constituents. The outcomes got from this study give a reasonable justification for the medicinal uses of Callistemon citrinus plant.

Keywords: Callistemon citrinus, flavanone, antioxidant activity, antimicrobial activity, essential oil, Myrtaceae

Procedia PDF Downloads 274

Authors: Shafiq Alam, Yen Ning Lee

Abstract:

Conventional hydrometallurgical processing of metals involves the use of large quantities of toxic chemicals. Realizing a need to develop sustainable technologies, extensive research studies are being carried out to recover and recycle base, precious and rare earth metals from their pregnant leach solutions (PLS) using green chemicals/biomaterials prepared from biomass wastes derived from agriculture, marine and forest resources. Our innovative research showed that bio-adsorbents prepared from such biomass wastes can effectively adsorb precious metals, especially gold after conversion of their functional groups in a very simple process. The highly effective ‘Adsorption-coupled-Reduction’ phenomenon witnessed appears promising for the potential use of this gold biosorption process in the mining industry. Proper management and effective use of biomass wastes as value added green chemicals will not only reduce the volume of wastes being generated every day in our society, but will also have a high-end value to the mining and mineral processing industries as those biomaterials would be cheap, but very selective for gold recovery/recycling from low grade ore, leach residue or e-wastes.

Keywords: biosorption, hydrometallurgy, gold, adsorption, reduction, biomass, sustainability

Procedia PDF Downloads 362

Authors: Pavel V. Balabanov, Daria A. Liubimova, Aleksandr P. Savenkov

Abstract:

The increase of technogenic and natural accidents, accompanied by air pollution, for example, by combustion products, leads to the necessity of respiratory protection. This work is devoted to the development of a calorimetric method and a device which allow investigating quickly the kinetics of carbon dioxide sorption by chemo-sorbents on the base of potassium superoxide in order to assess the protective properties of respiratory protective closed-circuit apparatus. The features of the traditional approach for determining the sorption properties in a thin layer of chemo-sorbent are described, as well as methods and devices, which can be used for the sorption kinetics study. The authors of the paper developed an approach (as opposed to the traditional approach) based on the power measurement of internal heat sources in the chemo-sorbent layer. The emergence of the heat sources is a result of the exothermic reaction of carbon dioxide sorption. This approach eliminates the necessity of chemical analysis of samples and can significantly reduce the time and material expenses during chemo-sorbents testing. The error of determining the volume fraction of adsorbed carbon dioxide by the developed method does not exceed 12%. Taking into account the efficiency of the method, we consider that it is a good alternative to traditional methods of chemical analysis under the assessment of the protection sorbents quality.

Keywords: carbon dioxide chemisorption, exothermic reaction, internal heat sources, respiratory protective apparatus

Procedia PDF Downloads 395

Authors: Chaiwat Kongsom, Vitoon Panyakul

Abstract:

The objective of this study was to assess the production and market of certified organic products in Thailand. A purposive sampling technique was used to identify a sample group of 154 organic entrepreneurs for the study. A survey and in-depth interview were employed for data collection. Also, secondary data from organic agriculture certification body and publications was collected. Then descriptive statistics and content analysis technique were used to describe about production and market of certified organic products in Thailand. Results showed that there were 9,218 farmers on 213,183.68 Rai (83,309.2 acre) of certified organic agriculture land (0.29% of national agriculture land). A total of 57.8% of certified organic agricultural lands were certified by the international certification body. Organic farmers produced around 71,847 tons/year and worth around THB 1,914 million (Euro 47.92 million). Excluding primary producers, 471 operators involved in the Thai organic supply chains, including processors, exporters, distributors, green shops, modern trade shops (supermarket shop), farmer’s markets and food establishments were included. Export market was the major market channel and most of organic products were exported to Europe and North America. The total Thai organic market in 2014 was estimated to be worth around THB 2,331.55 million (Euro 58.22 million), of which, 77.9% was for export and 22.06% was for the domestic market. The largest exports of certified organic products were processed foods (66.1% of total export value), followed by organic rice (30.4%). In the domestic market, modern trade was the largest sale channel, accounting for 59.48% of total domestic sales, followed by green shop (29.47%) and food establishment (5.85%). To become a center of organic farming and trading within ASEAN, the Thai organic sector needs to have more policy support in regard to agricultural chemicals, GMO, and community land title. In addition, appropriate strategies need to be developed.

Keywords: certified organic products, production, market, Thailand

Procedia PDF Downloads 313

Authors: Seyed Armin Hashemi, Somayeh Rahimzadeh

Abstract:

The urban green space and environment should be considered to be among the most fundamental elements of the sustainability of natural and human life in the new citizenship. The present research is intended to evaluate the impact of irrigation using urban wastewater of Cadmium (Cd) in the soil and leaves of the pine trees of Rasht in the forest territories of Rasht. For this purpose, following the exact specification of the geographical and topographical attributes of under treatment area, 100 sample trees were implemented randomly –systematically in each compound studied. Approaching the end of growth season, five trees were selected randomly in each of the plats and samples of leaves were collected from the parts near to the end of the crown and the part which was adjacent to the light. At the foot of each of the trees selected, a soil profile was dug and samples of soil were extracted from three depths of 0-20, centimeters. The measurements done in the laboratory showed that the density of nutritious elements of the samples of leaf and soil in the compound irrigated with wastewater .The results of the present research suggest that urban can be used as a source of irrigation whereas muck can be employed in forestation and irrigation with precise and particular supervision and control.

Keywords: irrigation, forestation, urban waste water, pine, wastewater

Procedia PDF Downloads 438

Authors: M. S. Mrudula, M. R. Gopinathan Nair

Abstract:

In order to utilize the natural rubber for developing new green polymeric materials for specialty applications, we have prepared natural rubber and polyethylene oxide based polymeric networks by two shot method. The polymeric networks thus formed have been used as chelating exchanger for metal ion binding. Chelating exchangers are, in general, coordinating copolymers containing one or more electron donor atoms such as N, S, O, and P that can form coordinate bonds with metals. Hydrogels are water- swollen network of hydrophilic homopolymer or copolymers. They acquire a great interest due to the facility of the incorporation of different chelating groups into the polymeric networks. Such polymeric hydrogels are promising materials in the field of hydrometallurgical applications and water purification due to their chemical stability. The current study discusses the swelling response of the polymeric networks as a function of time, temperature, pH and [NaCl] and sorption studies. Equilibrium swelling has been observed to depend on both structural aspects of the polymers and environmental factors. Metal ion sorption shows that these polymeric networks can be used for removal, separation, and enrichment of metal ions from aqueous solutions and can play an important role for environmental remediation of municipal and industrial wastewater.

Keywords: block copolymer, adsorption, chelating exchanger, swelling study, polymer, metal complexes

Procedia PDF Downloads 328

Authors: Sima Shakoorjavan, Mahdieh Eskafi, Dawid Stawski, Somaye Akbari

Abstract:

In this study, poly (amidoamine) dendritic material (PAMAM) and poly (acrylic acid) (PAA) as polycation and polyanion were deposited on surface charged polylactide (PLA) nonwoven to study the relationship of dye absorption capacity of layered-PLA with the number of deposited layers. To produce negatively charged-PLA, acrylic acid (AA) was grafted on the PLA surface (PLA-g-AA) through a chemical redox reaction with the strong oxidizing agent. Spectroscopy analysis, water contact measurement, and FTIR-ATR analysis confirm the successful grafting of AA on the PLA surface through the chemical redox reaction method. In detail, an increase in dye absorption percentage by 19% and immediate absorption of water droplets ensured hydrophilicity of PLA-g-AA surface; and the presence of new carbonyl bond at 1530 cm-¹ and a wide peak of hydroxyl between 3680-3130 cm-¹ confirm AA grafting. In addition, PLA as linear polyester can undergo aminolysis, which is the cleavage of ester bonds and replacement with amid bonds when exposed to an aminolysis agent. Therefore, to produce positively charged PLA, PAMAM as amine-terminated dendritic material was introduced to PLA molecular chains at different conditions; (1) at 60 C for 0.5, 1, 1.5, 2 hours of aminolysis and (2) at room temperature (RT) for 1, 2, 3, and 4 hours of aminolysis. Weight changes and spectrophotometer measurements showed a maximum in weight gain graph and K/S value curve indicating the highest PAMAM attachment at 60 C for 1 hour and RT for 2 hours which is considered as an optimum condition. Also, the emerging new peak around 1650 cm-1 corresponding to N-H bending vibration and double wide peak at around 3670-3170 cm-1 corresponding to N-H stretching vibration confirm PAMAM attachment in selected optimum condition. In the following, regarding the initial surface charge of grafted-PLA, lbl deposition was performed and started with PAA or PAMAM. FTIR-ATR results confirm chemical changes in samples due to deposition of the first layer (PAA or PAMAM). Generally, spectroscopy analysis indicated that an increase in layer number costed dye absorption capacity. It can be due to the partial deposition of a new layer on the previously deposited layer; therefore, the available PAMAM at the first layer is more than the third layer. In detail, in the case of layer-PLA starting lbl with negatively charged, having PAMAM as the first top layer (PLA-g-AA/PAMAM) showed the highest dye absorption of both cationic and anionic model dye.

Keywords: surface modification, layer-by-layer technique, dendritic materials, PAMAM, dye absorption capacity, PLA nonwoven

Procedia PDF Downloads 67

Authors: Youcef Serhane, Abdelkrim Bouzaza, Dominique Wolbert, Aymen Amin Assadi

Abstract:

Throughout history, the use of chemical weapons is not exclusive to combats between army corps; some of these weapons are also found in very targeted intelligence operations (political assassinations), organized crime, and terrorist organizations. To improve the speed of action, important technological devices have been developed in recent years, in particular in the field of protection and decontamination techniques to better protect and neutralize a chemical threat. In order to assess certain protective, decontaminating technologies or to improve medical countermeasures, tests must be conducted. In view of the great toxicity of toxic chemical agents from (real) wars, simulants can be used, chosen according to the desired application. Here, we present an investigation about using a photocatalytic filtering reactor (PFR) for highly contaminated environments containing diethyl sulfide (DES). This target pollutant is used as a simulant of CWA, namely of Yperite (Mustard Gas). The influence of the inlet concentration (until high concentrations of DES (1200 ppmv, i.e., 5 g/m³ of air) has been studied. Also, the conversion rate was monitored under different relative humidity and different flow rates (respiratory flow - standards: ISO / DIS 8996 and NF EN 14387 + A1). In order to understand the efficacity of pollutant neutralization by PFR, a kinetic model based on the Langmuir–Hinshelwood (L–H) approach and taking into account the mass transfer step was developed. This allows us to determine the adsorption and kinetic degradation constants with no influence of mass transfer. The obtained results confirm that this small configuration of reactor presents an extremely promising way for the use of photocatalysis for treatment to deal with highly contaminated environments containing real chemical warfare agents. Also, they can give birth to an individual protection device (an autonomous cartridge for a gas mask).

Keywords: photocatalysis, photocatalytic filtering reactor, diethylsulfide, chemical warfare agents

Procedia PDF Downloads 89

Authors: Lena Ernstgård, Aishwarya M. Dwivedi, Johan Lundström, Gunnar Johanson

Abstract:

A simple inexpensive olfactometer was constructed to enable valid measures of detection threshold of low concentrations of vapours of chemicals. The delivery system consists of seven syringe pumps, each connected to a Tedlar bag containing a predefined concentration of the test chemical in the air. The seven pumps are connected to a 8-way mixing valve which in turn connects to a birhinal nose piece. Chemical vapor of known concentration is generated by injection of an appropriate amount of the test chemical into a Tedlar bag with a known volume of clean air. Complete vaporization is assured by gentle heating of the bag from the outside with a heat flow. The six test concentrations are obtained by adding different volumes from the starting bag to six new Tedlar bags with known volumes of clean air. One bag contains clean air only. Thus, six different test concentrations and clean air can easily be tested in series by shifting the valve to new positions. Initial in-line measurement with a photoionization detector showed that the delivery system quickly responded to a shift in valve position. Thus 90% of the desired concentration was reached within 15 seconds. The concentrations in the bags are verified daily by gas chromatography. The stability of the system in terms of chemical concentration is monitored in real time by means of a photo-ionization detector. To determine lateralization thresholds, an additional pump supplying clean air is added to the delivery system in a way so that the nostrils can be separately and interchangeably be exposed to clean air and test chemical. Odor and lateralization thresholds were determined for three aldehydes; acrolein, crotonaldehyde, and hexanal in 20 healthy naïve individuals. Aldehydes generally have a strong odour, and the selected aldehydes are also considered to be irritating to mucous membranes. The median odor thresholds of the three aldehydes were 0.017, 0.0008, and 0.097 ppm, respectively. No lateralization threshold could be identified for acrolein, whereas the medians for crotonaldehyde and hexanal were 0.003 and 0.39 ppm, respectively. In conclusion, we constructed a simple, inexpensive olfactometer that allows for stable and easily measurable concentrations of vapors of the test chemical. Our test with aldehydes demonstrates that the system produces valid detection among volunteers in terms of odour and lateralization thresholds.

Keywords: irritation, odour delivery, olfactometer, smell

Procedia PDF Downloads 207

Authors: Rakesh Kumar, Shashi Janeoo, Ankit Dhiman, Siddharth Chopra

Abstract:

Arynes are versatile reactive intermediates that offer broad opportunities in green organic synthesis. Arynes are potential aryl group surrogates for the transition metal-free environment friendly arylation reactions. Regioselective arylations of quinolines were achieved by the reactions of quinoline N-oxides with aryne intermediates generated in situ from the Kobayashi precursors. Various 2-substituted quinolines provided 3-arylated-2-substituted quinolines under ambient conditions. Acridine N-oxides also reacted well and provided unusual 4-arylacridines. Various fluorine containing 2,3-diarylquinaolines prepared using this approach were evaluated for antibacterial activity and two compounds inhibited the drug-resistant strains of S-aureus with a good selectivity index. Further, the 2,3-diarylquinolines as the potential optoelectronic materials were prepared by the aryne chemistry approach and their optical and electronic properties for such applications are under study. The aryne intermediates provide an effective Green Chemistry tool to achieve versatile arylated heteroarenes for diverse applications.

Keywords: arynes, arylation, quinolines, acridines.

Procedia PDF Downloads 81

Authors: B. Sudhakara Reddy

Abstract:

In modern economy, energy is fundamental to virtually every product and service in use. It has been developed on the dependence of abundant and easy-to-transform polluting fossil fuels. On one hand, increase in population and income levels combined with increased per capita energy consumption requires energy production to keep pace with economic growth, and on the other, the impact of fossil fuel use on environmental degradation is enormous. The conflicting policy objectives of protecting the environment while increasing economic growth and employment has resulted in this paradox. Hence, it is important to decouple economic growth from environmental degeneration. Hence, the search for green energy involving affordable, low-carbon, and renewable energies has become global priority. This paper explores a transition to a sustainable energy system using the socio-economic-technical scenario method. This approach takes into account the multifaceted nature of transitions which not only require the development and use of new technologies, but also of changes in user behaviour, policy and regulation. The scenarios that are developed are: baseline business as usual (BAU) as well as green energy (GE). The baseline scenario assumes that the current trends (energy use, efficiency levels, etc.) will continue in future. India’s population is projected to grow by 23% during 2010 –2030, reaching 1.47 billion. The real GDP, as per the model, is projected to grow by 6.5% per year on average between 2010 and 2030 reaching US$5.1 trillion or $3,586 per capita (base year 2010). Due to increase in population and GDP, the primary energy demand will double in two decades reaching 1,397 MTOE in 2030 with the share of fossil fuels remaining around 80%. The increase in energy use corresponds to an increase in energy intensity (TOE/US $ of GDP) from 0.019 to 0.036. The carbon emissions are projected to increase by 2.5 times from 2010 reaching 3,440 million tonnes with per capita emissions of 2.2 tons/annum. However, the carbon intensity (tons per US$ of GDP) decreases from 0.96 to 0.67. As per GE scenario, energy use will reach 1079 MTOE by 2030, a saving of about 30% over BAU. The penetration rate of renewable energy resources will reduce the total primary energy demand by 23% under GE. The reduction in fossil fuel demand and focus on clean energy will reduce the energy intensity to 0.21 (TOE/US$ of GDP) and carbon intensity to 0.42 (ton/US$ of GDP) under the GE scenario. The study develops new ‘pathways out of poverty’ by creating more than 10 million jobs and thus raise the standard of living of low-income people. Our scenarios are, to a great extent, based on the existing technologies. The challenges to this path lie in socio-economic-political domains. However, to attain a green economy the appropriate policy package should be in place which will be critical in determining the kind of investments that will be needed and the incidence of costs and benefits. These results provide a basis for policy discussions on investments, policies and incentives to be put in place by national and local governments.

Keywords: energy, renewables, green technology, scenario

Procedia PDF Downloads 235

Authors: Emineh Tsegahun Gedif

Abstract:

Zinc oxide nanoparticles (ZnO NPs) have garnered significant attention due to their diverse applications encompassing catalytic, optical, photonic, and antibacterial properties. In this study, we successfully synthesized zinc oxide nanoparticles using a rapid, environmentally benign, and cost-effective method. Neem (Azadirachta indica) leaf extract served as the reducing agent for Zn (NO₃)₂.6H2O solution under optimized conditions (pH = 9). Qualitative screening techniques and FT-IR Spectroscopy confirmed the presence of active biomolecules such as flavonoids, phenolic groups, alkaloids, terpenoids, and tannins within the Neem leaf extract, both before and after reduction. The formation of ZnO NPs was visually evident through a distinct color change from colorless to light yellow. The biosynthesized nanoparticles underwent comprehensive characterization through UV-visible, FT-IR, and XRD spectroscopies. The reduction process proved to be straightforward and user-friendly, with UV-visible spectroscopy demonstrating a surface plasmon resonance (SPR) at 321 nm, unequivocally confirming the ZnO NP formation. X-ray diffraction analysis elucidated the crystal structure, revealing an average particle size of approximately 20 nm using Scherrer's equation based on the line width of the plane. Furthermore, the synthesized zinc oxide nanoparticles were evaluated for their antimicrobial properties against both Gram-positive and Gram-negative bacteria. The results showcased significant inhibitory activity, with the highest zone of inhibition observed against Escherichia coli (15 mm) and comparatively lower activity against Staphylococcus aureus. This research underscores the potential of Neem leaf extract-mediated synthesis of ZnO NPs as an eco-friendly and effective approach for various applications, including antibacterial agents.

Keywords: zinc oxide nanoparticles (ZnO NPs), bioreducing agent, green synthesis, antibacterial activity

Procedia PDF Downloads 50

Authors: Nonhlanhla Nkosi, Kulsum Kondiah

Abstract:

The toxicological manifestation of heavy metals motivates interest towards the development of a reliable, eco-friendly biosorption process. With that being said, the aim of the current study was to characterise the EPS from heavy-metal resistant bacteria isolated from acid mine decant on the West Rand, Gauteng, South Africa. To achieve this, six exopolysaccharide (EPS) producing, metal resistant strains (Pb101, Pb102, Pb103, Pb204, Co101, and Ni101) were identified as Bacillus safensis strain NBRC 100820, Bacillus proteolyticus, Micrococcus luteus, Enterobacter sp. Pb204, Bacillus wiedmannii and Bacillus zhangzhouensis, respectively with 16S rRNA sequencing. Thereafter, EPS was extracted using chemical (formaldehyde/NaOH) and physical (ultrasonification) methods followed by physicochemical characterisation of carbohydrate, DNA, and protein contents using chemical assays and spectroscopy (FTIR- Fourier transformed infrared and 3DEEM- three-dimensional excitation-emission matrix fluorescence spectroscopy). EPS treated with formaldehyde/NaOH showed better recovery of macromolecules than ultrasonification. The results of the present study showed that carbohydrates were more abundant than proteins, with carbohydrate and protein concentrations of 8.00 mg/ml and 0.22 mg/ml using chemical method in contrast to 5.00 mg/ml and 0.77 mg/ml using physical method, respectively. The FTIR spectroscopy results revealed that the extracted EPS contained hydroxyl, amide, acyl, and carboxyl groups that corresponded to the aforementioned chemical analysis results, thus asserting the presence of carbohydrates, DNA, polysaccharides, and proteins in the EPS. These findings suggest that identified functional groups of EPS form surface charges, which serve as the binding sites for suspended particles, thus possibly mediating adsorption of divalent cations and heavy metals. Using the extracted EPS in the development of a cost-effective biosorption solution for industrial wastewater treatment is attainable.

Keywords: biosorbent, exopolysaccharides, heavy metals, wastewater treatment

Procedia PDF Downloads 139

Authors: G. Çelik Gül, F. Kurtuluş

Abstract:

Rare earths containing complex metal oxides have drawn much attention due to physical, chemical and optical properties which make them feasible in so many areas such as non-linear optical materials and ion exchanger. We have researched a systematic study to obtain rare earth containing zirconium molybdate compound, characterization, investigation of crystal system and calculation of unit cell parameters.  After a successful synthesis of Nd₂Zr₃(MoO₄)₉ which is a member of rare earth metal containing complex oxides family, X-ray diffraction (XRD), High Score Plus/Rietveld refinement analysis, and Fourier Transform Infrared Spectroscopy (FTIR) were completed to determine the crystal structure. Morphological properties and elemental composition were determined by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. Thermal properties were observed via Thermogravimetric-differential thermal analysis (TG/DTA).

Keywords: Nd₂Zr₃(MoO₄)₉, powder x-ray diffraction, solid state synthesis, zirconium molybdates

Procedia PDF Downloads 384

Authors: Shih-Hao Chen, Chi-Wai Chow

Abstract:

Multiple-input and multiple-output (MIMO) scheme can extend the transmission capacity for the light-emitting-diode (LED) visible light communication (VLC) system. The MIMO VLC system using the popular mobile-phone camera as the optical receiver (Rx) to receive MIMO signal from n x n Red-Green-Blue (RGB) LED array is desirable. The key step of decoding the received RGB LED array signals is detecting the direction of received array signals. If the LED transmitter (Tx) is rotated, the signal may not be received correctly and cause an error in the received signal. In this work, we propose and demonstrate a novel hierarchical transmission scheme which can reduce the computation complexity of rotation detection in LED array VLC system. We use the n x n RGB LED array as the MIMO Tx. A novel two dimension Hadamard coding scheme is proposed and demonstrated. The detection correction rate is above 95% in the indoor usage distance. Experimental results confirm the feasibility of the proposed scheme.

Keywords: Visible Light Communication (VLC), Multiple-input and multiple-output (MIMO), Red-Green-Blue (RGB), Hadamard coding scheme

Procedia PDF Downloads 404

Authors: Abdullah M. Alzahrani

Abstract:

The unicellular alga Chlorella vulgaris was isolated from Al-Asfar Lake, which is located in the Al-Ahsa province of Saudi Arabia. Two different isolates were sub-cultured under laboratory conditions. The wild type was grown under a regular concentration of copper, whereas the other isolate was grown under a progressively increasing copper concentration. An Inter Simple Sequence Repeats (ISSR) analysis was performed using DNA isolated from the wild type and tolerant strains. The sum of the scored bands of the wild type was 155, with 100 (64.5%) considered to be polymorphic bands, whereas the resistant strain displayed 147 bands, with 92 (62.6%) considered to be polymorphic bands. The sum of the scored bands of a mixed sample was 117 bands, of which only 4 (3.4%) were considered to be polymorphic. The average Nei's genetic diversity (h) and Shannon-Weiner diversity indices (I) were 0.3891 and 0.5394, respectively. These results clearly indicate that the adaptation to a high level of copper in Chlorella vulgaris is not merely physiological but rather driven by modifications at the genomic level.

Keywords: chlorella vulgaris, copper tolerance, genetic diversity, green algae

Procedia PDF Downloads 419

Authors: Hande Aladağ, Gökçe Aydın

Abstract:

The world’s population is increasing continuously and rapidly. Moreover, there are other problems such as the decline of natural energy resources, global warming, and environmental pollution. These facts have made sustainability an important and primary topic from future planning perspective. From this perspective, constituting sustainable cities and communities can be considered as one of the key issues in terms of sustainable development goals. The concept of sustainable cities can be evaluated under three headings such as green/sustainable buildings, self – contained cities and sustainable transportation. This study only concentrates on how to form and support a sustainable urban transportation system to contribute to the sustainable urbanization. Urban transportation system inevitably requires many engineering projects with various sizes. Engineering projects generally have four phases, in the following order: Planning, design, construction, operation. The order is valid but there are feedbacks from every phase to every phase in its upstream. In this regard, engineering projects are iterative processes. Sustainability is an integrated and comprehensive concept thus it should be among the primary concerns in every phase of transportation projects. In the study, a meta-analysis will be performed on the related studies in the literature. It is targeted and planned that, as a result of the findings of this meta-analysis, a framework for the list of principles and actions for sustainable transport will be formed. The meta-analysis will be performed to point out and clarify sustainability approaches in every phase of the related engineering projects, with also paying attention to the iterative nature of the process and relative contribution of the action for the outcomes of the sustainable transportation system. However, the analysis will not be limited to the engineering projects, non-engineering solutions will also be included in the meta-analysis. The most important contribution of this study is a determination of the outcomes of a sustainable urban transportation system in terms of energy efficiency, resource preservation and related social, environmental and economic factors. The study is also important because it will give light to the engineering and management approaches to achieve these outcomes.

Keywords: meta-analysis, sustainability, sustainable cities, sustainable urban transportation, urban transportation

Procedia PDF Downloads 315

Authors: W. Walke, J. Przondziono, K. Nowińska

Abstract:

The study comprises evaluation of suitability of passive layer created on the surface of AISI 316L stainless steel for products that are intended to have contact with blood. For that purpose, prior to and after chemical passivation, samples were subject to 7 day exposure in artificial plasma at the temperature of T=37°C. Next, tests of metallic ions infiltration from the surface to the solution were performed. The tests were performed with application of spectrometer JY 2000, by Yobin – Yvon, employing Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). In order to characterize physical and chemical features of electrochemical processes taking place during exposure of samples to artificial plasma, tests with application of electrochemical impedance spectroscopy were suggested. The tests were performed with application of measuring unit equipped with potentiostat PGSTAT 302n with an attachment for impedance tests FRA2. Measurements were made in the environment simulating human blood at the temperature of T=37°C. Performed tests proved that application of chemical passivation process for AISI 316L stainless steel used for production of goods intended to have contact with blood is well-grounded and useful in order to improve safety of their usage.

Keywords: AISI 316L stainless steel, chemical passivation, artificial plasma, ions infiltration, EIS

Procedia PDF Downloads 250

Authors: R. L. P. De Lima, F. C. B. Boogaard, R. E. De Graaf-Van Dinther

Abstract:

Blue-green algae blooms (cyanobacteria) is currently a relevant ecological problem that is being addressed by most water authorities in the Netherlands. These can affect recreation areas by originating unpleasant smells and toxins that can poison humans and animals (e.g. fish, ducks, dogs). Contamination events usually take place during summer months, and their frequency is increasing with climate change. Traditional monitoring of this bacteria is expensive, labor-intensive and provides only limited (point sampling) information about the spatial distribution of algae concentrations. Recently, a novel handheld sensor allowed water authorities to quicken their algae surveying and alarm systems. This study converted the mentioned algae sensor into a mobile platform, by combining it with an underwater remotely operated vehicle (also equipped with other sensors and cameras). This provides a spatial visualization (mapping) of algae concentrations variations within the area covered with the drone, and also in depth. Measurements took place in different locations in the Netherlands: i) lake with thick silt layers at the bottom, very eutrophic former bottom of the sea and frequent / intense mowing regime; ii) outlet of waste water into large reservoir; iii) urban canal system. Results allowed to identify probable dominant causes of blooms (i), provide recommendations for the placement of an outlet, day-night differences in algae behavior (ii), or the highlight / pinpoint higher algae concentration areas (iii). Although further research is still needed to fully characterize these processes and to optimize the measuring tool (underwater drone developments / improvements), the method here presented can already provide valuable information about algae behavior and spatial / temporal variability and shows potential as an efficient monitoring system.

Keywords: blue-green algae, cyanobacteria, underwater drones / ROV / AUV, water quality monitoring

Procedia PDF Downloads 188

Authors: Friman Hen, Banner Ifaa, Shalom-Tuchin Bosmat, Einav Yulia

Abstract:

The action learning course is an academic course which involves academic learning and social activities. The courses deal with processes and social challenges, reveal different ideologies, and develop critical thinking and pragmatic ideas. Students receive course credits and a grade for being part of such courses. Participating students enroll in courses that involve action and activities to engage in the experiential learning process, thereby creating a dialogue and cross-fertilization between being taught in the classroom and experiencing the reality in the real world. A learning experience includes meeting with social organizations, institutions, and state authorities and carrying out practical work with diverse populations. Through experience, students strengthen their academic skills, formulate ethical attitudes toward reality, develop professional and civilian perspectives, and realize how they can influence their surrounding in the present and the hereafter. Under the guidance and supervision of Dr. Hen Friman, H.I.T. has built an innovative course that combines action and activities to increase the awareness and accessibility of the community in an experiential way. The end goal is to create Green Ambassadors—children with a high level of environmental awareness. This course is divided into two parts. The first part, focused on frontal teaching, delivers knowledge from extensive environmental fields to students. These areas include introduction to ecology, the process of electricity generation, air pollution, renewable energy, water economy, waste and recycling, and energy efficiency (first stage). In addition to the professional content in the environment field, students learn the method of effective and experiential teaching to younger learners (4 to 8 years old). With the attainment of knowledge, students are divided into operating groups. The second part of the course shows how the theory becomes practical and concrete. At this stage, students are asked to introduce to the first- and second-graders of ‘Revivim’ School in Holon a lesson of 90 minutes focused on presenting the issues and their importance during the course (second stage). This course is the beginning of a paradigm shift regarding energy usage in the modern society in Israel. The objective of the course is to expand worldwide and train the first and second-graders, and even pre-schoolers, in a wide scope to increase population awareness rate, both in Israel and all over the world, for a green future.

Keywords: air pollution, green ambassador, recycling, renewable energy

Procedia PDF Downloads 229

Authors: Amandeep Kaur, Sangeeta Sharma

Abstract:

Keeping in view the serious entanglement of heavy metals ( Pb+2 and Ni+2) ions in an aqueous environment, a rapid search for efficient adsorbents for the adsorption of heavy metals has become highly desirable. In this quest, green synthesized Fe np’s have gathered attention because of their excellent adsorption capability of heavy metals from aqueous solution. This research report aims at the fabrication of Fe np’s using the fruit Cucumis melo and leaves of Ficus virens via a biogenic synthesis route. Further, synthesized CM-Fe-np’s and FV-Fe-np’s have been tested as potential bio-adsorbents for the removal of Pb+2 and Ni+2 by carrying out adsorption batch experiments. The influence of myriad parameters like initial concentration of Pb/Ni (5,10,15,20,25 mg/L), contact time (10 to 200 min.), adsorbent dosage (0.5, 0.10, 0.15 mg/L), shaking speed (120 to 350 rpm) and pH value (6,7,8,9) has been investigated. The maximum removal with CM-Fe-np’s and FV-Fe-np’s has been achieved at pH 7, metal conc. 5 mg/L, dosage 0.9 g/L, shaking speed 200 rpm and reaction contact time 200 min during the adsorption experiment. The results obtained are found to be in accordance with Freundlich and Langmuir's adsorption models; consequently, they could be highly applicable to the wastewater treatment plant.

Keywords: adsorption, biogenic synthesis, nanoparticles, nickel, lead

Procedia PDF Downloads 71

Authors: Chen Xi, Liu Xuebing, Lao Xuerui, Kuan Sinman, Jiang Yike, Wang Hanwei, Yang Xiaolang, Zhou Junjie, Xie Jinpeng

Abstract:

Climate change is a global problem facing humanity and this is now the consensus of the mainstream scientific community. In accordance with the carbon peak and carbon neutral targets and visions set out in the United Nations Framework Convention on Climate Change, the Kyoto Protocol and the Paris Agreement, this project uses the City Intelligent Model (CIM) and Artificial Intelligence Machine Vision (ICR) as the core technologies to accurately quantify low carbon behaviour into green corn, which is a means of guiding ecologically sustainable living patterns. Using individual communities as management units and blockchain as a guarantee of fairness in the whole cycle of green currency circulation, the project will form a modern resident carbon track management system based on the principle of enhancing the ecological resilience of communities and the cohesiveness of community residents, ultimately forming an ecologically sustainable smart village that can be self-organised and managed.

Keywords: urban planning, urban governance, CIM, artificial Intelligence, sustainable development

Procedia PDF Downloads 68

Authors: Yasmina Houda Bendahma, Tewfik Bouchaour, Meriem Merad, Ulrich Maschke

Abstract:

The purpose of this work is to study retention of dye dissolved in distilled water, by an hydrophilic acrylic polymer network. The polymer network considered is Poly (2-hydroxyethyl methacrylate) (PHEMA): it is prepared by photo-polymerization under UV irradiation in the presence of a monomer (HEMA), initiator and an agent cross-linker. PHEMA polymer network obtained can be used in the retention of dye molecules present in the wastewater. The results obtained are interesting in the study of the kinetics of swelling and de-swelling of cross linked polymer networks PHEMA in colored aqueous solutions. The dyes used for retention by the PHEMA networks are eosin Y and Malachite Green, dissolved in distilled water. Theoretical conformational study by a simplified molecular model of system cross linked PHEMA / dye (eosin Y and Malachite Green), is used to simulate the retention phenomenon (or Docking) dye molecules in cavities in nano-domains included in the PHEMA polymer network.

Keywords: dye retention, molecular modeling, photochemically crosslinked polymer network, swelling deswelling, PHEMA, HEMA

Procedia PDF Downloads 348

Authors: Li Ni, Pen ManMan, Li KenLi

Abstract:

Clustering is an intensive research for some years because of its multifaceted applications, such as biology, information retrieval, medicine, business and so on. The expectation maximization (EM) is a kind of algorithm framework in clustering methods, one of the ten algorithms of machine learning. Traditionally, optimization of objective function has been the standard approach in EM. Hence, research has investigated the utility of evolutionary computing and related techniques in the regard. Chemical Reaction Optimization (CRO) is a recently established method. So the property embedded in CRO is used to solve optimization problems. This paper presents an algorithm framework (EM-CRO) with modified CRO operators based on EM cluster problems. The hybrid algorithm is mainly to solve the problem of initial value sensitivity of the objective function optimization clustering algorithm. Our experiments mainly take the EM classic algorithm:k-means and fuzzy k-means as an example, through the CRO algorithm to optimize its initial value, get K-means-CRO and FKM-CRO algorithm. The experimental results of them show that there is improved efficiency for solving objective function optimization clustering problems.

Keywords: chemical reaction optimization, expection maimization, initia, objective function clustering

Procedia PDF Downloads 693

Authors: Tamirat Solomon, Aberash Yohannis, Efrem Gulfo

Abstract:

The plantation of trees, which harmonizes the agroecology of the environment, has been implemented in Ethiopia with great concern for a noticeably degraded environment. This study was designed to evaluate the effectiveness of green legacy, species selection and, the rate of survival, and the management status in the study areas. A systematic sampling method was employed to collect the required data from 144 quadrants measuring a 15m radius with an interval of 40m apart. Additionally, 244 sample households were selected for the socioeconomic study in addition to secondary data collected from office recordings. The data collected was analyzed using multivariate analysis, considering exposure and outcome variables. The findings of this study indicated that four exotic tree species, namely; A. salgina, C. fistula, A. indica, and G. robusta, were commonly selected tree species for degraded land restoration in the study areas. Among the seedlings planted at the four study sites, a total of 79.9% survived, and A. salgina was the dominant and best performed species, A. indica was the least survived species in the entire study area. The age of the seedling before planting significantly (p = 0.05) affected the survival potential of most seedlings of species, and the majority (82%) of local communities expressed their positive attitudes and willingness to manage the restoration works in the study areas. It was recommended to consider the inclusion of native species in the restoration effort and evaluate the co-existence of native flora with exotic and its competition for nutrients, water, and light in addition to the invading potentials in the ecosystem. In general, before embarking on degraded land restoration, species selection, adequate preparation of seedlings, and species diversity composition that exactly fit the socioeconomic and ecological demands of the areas must get the attention for the success of the restoration.

Keywords: plantation forest, degraded land, forest restoration, plantation survival, species selection

Procedia PDF Downloads 60

Authors: Obradith Caicedo, Paola Devia

Abstract:

Methylene blue (MB) and malachite green (MG) are substances commonly used in classrooms for academic purposes. Nevertheless, in most cases, there is no adequate disposal of this type of waste, their presence in the environment affects ecosystems due to the presence of color and the reduction of photosynthetic processes. In this work, we evaluated properties of fibers of Luffa cylindrica in removal from dyes of aqueous solutions through an adsorption process. The point of zero charge, acid and basic sites was also investigated. The best conditions of the adsorption process were determined under a discontinuous system, evaluating an interval of the variables 2 3 : pH value, particle size of the adsorbent and contact time. The temperature (18ºC), agitation (220 rpm) and adsorbent dosage (10g/L) were constant. Measurements were made using UV- Visible spectrophotometry. The point of zero charge for Luffa cylindrica was 4,3. The number of acidic and basic sites was 2.441 meq/g and 1,009 meq/g respectively. These indicate a prevalence of acid groups. The maximum dye sorption was found to be at a pH of 5,5 (97,1 % for MB) and 5,0 (97,7% for MG) and particle size of the adsorbent 850 µm. The equilibrium uptake was attained within 60 min. With this study, it has been shown that Luffa cylindrica can be used as efficient adsorbent for the removal of methylene blue, and malachite green from aqueous solution in classrooms.

Keywords: adsorption, dye removal, low-cost adsorbents, Luffa cylindrical

Procedia PDF Downloads 180

Authors: Néné Gallé Kide, Mamadou Dia, Lemhaba Ould Yarba, Youssouf Kone, Fatimetou Mint Khalil, Hajar Bouksir, Ghislane Salhi, Younès Saoud

Abstract:

The diet of Sarotherodon melanotheron and Tilapia guineensis were investigated in the National Park of Banc d'Arguin (PNBA) from September 2012 to October 2013. A total of 499 individuals ranging in size between 219 and 400 mm total length of S. melanotheron (253 males and 246 females), and 280 individuals of T.guineensis (229 males and 51 females) ranged between 180 and 424mm total length. We used for studying the feeding habits of both two species the frequency of occurrence method. The coefficient of emptiness was 40.88% for S. melanotheron and 38.57% for T. guineensis. Both two species were herbivorous and very close feedings. Their diet consists of Seagrass, green, red, blue, and brown algae, diatoms, gastropods, bivalves, Crustaceans, and mud. The Seagrass and green algae were prey preference of these two species. The diet feeding showed that the composition varies slightly depending on the season and size of individuals.

Keywords: Cichlidae, trophic ecology, National park, Banc d'Arguin, Mauritania

Procedia PDF Downloads 775

Authors: Simon Peter Wafula, Ziporah Nakabazzi Kitooke

Abstract:

Graphene is a carbon allotrope made of a two-dimensional shape. This material has got a number of materials researchers’ interest due to its properties that are special compared to ordinary material. Graphene is thought to enhance a number of material properties in the manufacturing, energy, and construction industries. Many studies consider graphene to be a wonder material, just like plastic in the 21st century. This shows how much should be invested in graphene research. This review highlights the status of graphene extracted from various biomass sources together with their appropriate extraction techniques, including the pretreatment methods for a better product. The functional groups and structure of graphene extracted using several common methods of synthesis are in this paper as well. The review explores methods like chemical vapor deposition (CVD), hydrothermal, chemical exfoliation method, liquid exfoliation, and Hummers. Comparative analysis of the various extraction techniques gives an insight into each of their advantages, challenges, and potential scalability. The review also highlights the pretreatment process for biomass before carbonation for better quality of bio-graphene. The various graphene modes, as well as their applications, are in this study. Recommendations for future research for improving the efficiency and sustainability of bio-graphene are highlighted.

Keywords: exfoliation, nanomaterials, biochar, large-scale, two-dimension

Procedia PDF Downloads 32