Search results for: Food contacting materials

Authors: Misook Ahn

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This study examined the Digital Curriculum Repository (DCR) project initiated at Defense Language Institute Foreign Language Center (DLIFLC). The purpose of the DCR is to build a centralized curriculum infrastructure, preserve all curriculum materials, and provide academic service to users (faculty, students, or other agencies). The DCR collection includes core language curriculum materials developed by each language school—foreign language textbooks, language survival kits, and audio files currently in or not in use at the schools. All core curriculum materials with audio and video files have been coded, collected, and preserved at the DCR. The DCR website was designed with MS SharePoint for easy accessibility by the DLIFLC’s faculty and students. All metadata for the collected curriculum materials have been input by language, code, year, book type, level, user, version, and current status (in use/not in use). The study documents digital curriculum preservation planning, actions, and challenges, including collecting, coding, collaborating, designing DCR SharePoint, and policymaking. DCR Survey data is also collected and analyzed for this research. Based on the finding, the study concludes that the mandatory policy for the DCR system and collaboration with school leadership are critical elements of a successful repository system. The sample collected items, metadata, and DCR SharePoint site are presented in the evaluation section.

Keywords: MS share point, digital preservation, repository, policy

Procedia PDF Downloads 147

Authors: Utkarsh Goley

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Leather has been a valued material for clothing and accessories for centuries, and its use has evolved along with fashion trends and technological advancements. From ancient times when leather was used for practical purposes, to the modern fashion industry, where it is used for both functional and decorative purposes, leather has undergone significant changes in its production and usage. In recent years, there has been a growing awareness of ethical and sustainable fashion, leading to a shift towards alternative materials and production methods. The leather industry has responded to this by exploring new techniques and materials, such as vegetable-tanned leather and leather substitutes made from plant-based materials. The evolution of leather in the fashion industry is also closely tied to cultural and social trends. The use of leather has been associated with rebellion and counterculture in the past, and today it is often used to evoke a sense of luxury and sophistication. Despite the challenges and controversies surrounding its production, leather continues to be a popular material in the fashion industry, with designers and consumers alike valuing its durability, versatility, and aesthetic appeal. As fashion continues to evolve, so will the role and use of leather in the industry. This research paper provides a detailed overview of the evolution of leather in the fashion industry throughout the different decades and centuries.

Keywords: evolution, fashion, leather, sustainable

Procedia PDF Downloads 77

Authors: M. N. Boukhatem, M. A. Ferhat, K. Mansour

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Bovine raw milk represents a favorable environment for the growth of several food-spoilage strains and some pathogens. It must meet stringent standards to ensure the highest microbiological and toxicological qualities.In order to assess the microbiological risks associated with the consumption of this food, we conducted this study to determine the microbiological quality of bovine raw milk (54 samples) commercialized at the state of Blida (Algeria). The samples analyzed were unsatisfactory in terms of total flora where 61.11% of samples were considered as non acceptable in terms of quality standards, fecal coliforms (40.74%), fecal streptococci (55.55%) and staphylococci (74.07%). Salmonella and Clostridium strains were not detected in all the samples. Furthermore, antibiotic residues were found in 26% of analysed samples. These results reflect non-compliance with the rules of good hygiene practices at milking, storage, transportatio, and sale of milk. Bovine raw milk consumed presents a serious health risk to the population of the study areas.The livestock coaching actors and dissemination of good hygiene practices throughout the production chain are needed to improve the quality of local milk.

Keywords: bovine raw milk, microbiological quality, fecal coliforms, antibiotic residue, Blida state

Procedia PDF Downloads 223

Authors: Rebecca Bach, Evgenia Kanli, Nihat Kiziltoprak, Linda Hildebrand, Ulrich Knaack, Jens Schneider

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The building industry has a high demand for resources and at the same time is responsible for a significant amount of waste created worldwide. Today's building components need to contribute to the protection of natural resources without creating waste. This is defined in the product development phase and impacts the product’s degree of being cycle-oriented. Paper-based materials show advantage due to their renewable origin and their ability to incorporate different functions. Besides the ecological aspects like renewable origin and recyclability the main advantages of paper materials are its light-weight but stiff structure, the optimized production processes and good insulation values. The main deficits from building technology’s perspective are the material's vulnerability to humidity and water as well as inflammability. On material level, those problems can be solved by coatings or through material modification. On construction level intelligent setup and layering of a building component can improve and also solve these issues. The target of the present work is to provide an overview of developed building components and construction typologies mainly made from paper materials. The research is structured in four parts: (1) functions and requirements, (2) preselection of paper-based materials, (3) development of building components and (4) evaluation. As part of the research methodology at first the needs of the building sector are analyzed with the aim to define the main areas of application and consequently the requirements. Various paper materials are tested in order to identify to what extent the requirements are satisfied and determine potential optimizations or modifications, also in combination with other construction materials. By making use of the material’s potentials and solving the deficits on material and on construction level, building components and construction typologies are developed. The evaluation and the calculation of the structural mechanics and structural principals will show that different construction typologies can be derived. Profiles like paper tubes can be used at best for skeleton constructions. Massive structures on the other hand can be formed by plate-shaped elements like solid board or honeycomb. For insulation purposes corrugated cardboard or cellulose flakes have the best properties, while layered solid board can be applied to prevent inner condensation. Enhancing these properties by material combinations for instance with mineral coatings functional constructions mainly out of paper materials were developed. In summary paper materials offer a huge variety of possible applications in the building sector. By these studies a general base of knowledge about how to build with paper was developed and is to be reinforced by further research.

Keywords: construction typologies, cycle-oriented construction, innovative building material, paper materials, renewable resources

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Authors: Abioye A. Oyenuga, Rao Bhamidiarri

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Hurling a successful Construction and Demolition Waste (C&DW) recycling operation around the globe is a challenge today, predominantly because secondary materials markets are yet to be integrated. Reducing, Reusing and recycling of (C&DW) have been employed over the years, and various techniques have been investigated. However, the economic and environmental viability of its application seems limited. This paper discusses the costs and benefits in using secondary materials and focus on investigating reuse and recycling process for five major types of construction materials: concrete, metal, wood, cardboard/paper, and plasterboard. Data obtained from demolition specialist and contractors are considered and evaluated. With the date source, the research paper found that construction material recovery process fully incorporate the 3R’s process and shows how energy recovery by means of 3R's principles can be evaluated. This scrutiny leads to the empathy of grand challenges in construction material recovery process. Recommendations to deepen material recovery process are also discussed.

Keywords: construction and demolition waste (C&DW), 3R concept, recycling, reuse, waste management, UK

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Authors: Mahmoud H. Aboul-Ela, Riham R. Mohamed, Magdy W. Sabaa

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Synthesis of cross-linked hydrogels composed of trimethyl chitosan (TMC) and poly(vinyl alcohol) (PVA) in different weight ratios in presence of glutaraldehyde as cross-linking agent. Characterization of the prepared hydrogels was done using FTIR, XRD, SEM and TGA. The prepared hydrogels were investigated as adsorbent materials for some transition metal ions from their aqueous solutions. Moreover, the swell ability of the prepared hydrogels was also investigated in both acidic and alkaline pHs, as well as in simulated body fluid (SBF).

Keywords: trimethyl chitosan, hydrogels, metal uptake, superabsorbent materials

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Authors: Isiya Shinkafi Salihu

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Open education resources (OER) are open learning materials in different formats, course content and context to support learning globally. This study investigated the level of awareness of Hospitality and Tourism OER among students in the Department of Tourism and Hotel Management in a University. Specifically, it investigated students’ awareness, use and accessibility of OER in learning. The research design method used was the quantitative approach, using an online questionnaire. The thesis research shows that respondents frequently use OER but with little knowledge of the content and context of the material. Most of the respondents’ have little knowledge about the concept even though they use it. Information and communication technologies are tools for information gathering, social networking and knowledge sharing and transfer. OER are open education materials accessible online such as curriculum, maps, course materials, and videos that users create, adapt, reuse for learning and research. Few of the respondents that used OER in learning faced some challenges such as high cost of data, poor connectivity and lack of proper guidance. The results suggest a lack of awareness of OER among students in the faculty of tourism and the need for support from the teachers in the utilization of OER. The thesis also reveals that some of the international students are accessing the internet as beginners in their studies which require guidance. The research, however, recommends that further studies should be conducted to other faculties.

Keywords: creative commons, open education resources, open licenses, information and communication technology

Procedia PDF Downloads 166

Authors: Pantea Salehizadeh, Martin P. Bucknall, Robert Driscoll, Jayashree Arcot, George Srzednicki

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Banana is one of the most important crops produced in large quantities in tropical and sub-tropical countries. Of the total plant material grown, approximately 40% is considered waste and left in the field to decay. This practice allows fungal diseases such as Sigatoka Leaf Spot to develop, limiting plant growth and spreading spores in the air that can cause respiratory problems in the surrounding population. The pseudostem is considered a waste residue of production (60 to 80 tonnes/ha/year), although it is a good source of dietary fiber and volatile organic compounds (VOC’s). Strategies to process banana pseudostem into palatable, nutritious and marketable food materials could provide significant social and economic benefits. Extraction of VOC’s with desirable odor from dried and fresh pseudostem could improve the smell of products from the confectionary and bakery industries. Incorporation of banana pseudostem flour into bakery products could provide cost savings and improve nutritional value. The aim of this study was to determine the effects of drying methods and different banana species on the profile of volatile aroma compounds in dried banana pseudostem. The banana species analyzed were Musa acuminata and Musa balbisiana. Fresh banana pseudostem samples were processed by either freeze-drying (FD) or heat pump drying (HPD). The extraction of VOC’s was performed at ambient temperature using vacuum distillation and the resulting, mostly aqueous, distillates were analyzed using headspace solid phase microextraction (SPME) gas chromatography – mass spectrometry (GC-MS). Optimal SPME adsorption conditions were 50 °C for 60 min using a Supelco 65 μm PDMS/DVB Stableflex fiber1. Compounds were identified by comparison of their electron impact mass spectra with those from the Wiley 9 / NIST 2011 combined mass spectral library. The results showed that the two species have notably different VOC profiles. Both species contained VOC’s that have been established in literature to have pleasant appetizing aromas. These included l-Menthone, D-Limonene, trans-linlool oxide, 1-Nonanol, CIS 6 Nonen-1ol, 2,6 Nonadien-1-ol, Benzenemethanol, 4-methyl, 1-Butanol, 3-methyl, hexanal, 1-Propanol, 2-methyl- acid، 2-Methyl-2-butanol. Results show banana pseudostem VOC’s are better preserved by FD than by HPD. This study is still in progress and should lead to the optimization of processing techniques that would promote the utilization of banana pseudostem in the food industry.

Keywords: heat pump drying, freeze drying, SPME, vacuum distillation, VOC analysis

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Authors: António Inês, Ana Guimarães, José Maria, Vânia Laranjo, Armando Venâncio, Luís Abrunhosa

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Lactic acid bacteria (LAB) play a key role in the biopreservation of a wide range of fermented food products, such as yogurt, cheese, fermented milks, meat, fish, vegetables (sauerkraut, olives and pickles), certain beer brands, wines and silage, allowing their safe consumption, which gave to these bacteria a GRAS (Generally Recognised as Safe) status. Besides that, the use of LAB in food and feed is a promising strategy to reduce the exposure to dietary mycotoxins, improving their shelf life and reducing health risks, given the unique mycotoxin decontaminating characteristic of some LAB. Mycotoxins present carcinogenic, mutagenic, teratogenic, neurotoxic and immunosuppressive effects over animals and Humans, being the most important ochratoxin A (OTA), aflatoxins (AFB1), trichothecenes, zearalenone (ZEA), fumonisin (FUM) and patulin. In a previous work of our group it was observed OTA biodegradation by some strains of Pediococcus parvulus isolated from Douro wines. So, the aim of this study was to enlarge the screening of the biodetoxification over more mycotoxins besides OTA, including AFB1, and ZEA. This ability was checked in a collection of LAB isolated from vegetable (wine, olives, fruits and silage) and animal (milk and dairy products, sausages) sources. All LAB strains were characterized phenotypically (Gram, catalase) and genotypically. Molecular characterisation of all LAB strains was performed using genomic fingerprinting by MSP-PCR with (GTG)5 and csM13 primers. The identification of the isolates was confirmed by 16S rDNA sequencing. To study the ability of LAB strains to degrade OTA, AFB1 and ZEA, a MRS broth medium was supplemented with 2.0 μg/mL of each mycotoxin. For each strain, 2 mL of MRS supplemented with the mycotoxins was inoculated in triplicate with 109 CFU/mL. The culture media and bacterial cells were extracted by the addition of an equal volume of acetonitrile/methanol/acetic acid (78:20:2 v/v/v) to the culture tubes. A 2 mL sample was then collected and filtered into a clean 2 mL vial using PP filters with 0.45 μm pores. The samples were preserved at 4 °C until HPLC analysis. Among LAB tested, 10 strains isolated from milk were able to eliminate AFB1, belonging to Lactobacillus casei (7), Lb. paracasei (1), Lb. plantarum (1) and 1 to Leuconostoc mesenteroides. Two strains of Enterococcus faecium and one of Ec. faecalis from sausage eliminated ZEA. Concerning to strains of vegetal origin, one Lb. plantarum isolated from elderberry fruit, one Lb. buchnerii and one Lb. parafarraginis both isolated from silage eliminated ZEA. Other 2 strains of Lb. plantarum from silage were able to degrade both ZEA and OTA, and 1 Lb. buchnerii showed activity over AFB1. These enzymatic activities were also verified genotypically through specific gene PCR and posteriorly confirmed by sequencing analysis. In conclusion, due the ability of some strains of LAB isolated from different sources to eliminate OTA, AFB1 and ZEA one can recognize their potential biotechnological application to reduce the health hazards associated with these mycotoxins. They may be suitable as silage inoculants or as feed additives or even in food industry.

Keywords: bio-detoxification, lactic acid bacteria, mycotoxins, food and feed

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Authors: Ramadhani Yasyfi Cysela, Adinda Syifa Azhari, Eleonora Agustine

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The World Health Organization (WHO) estimates that about a quarter of the diseases facing mankind today occur due to environmental pollution. The soil is a part of environment that have a widespread problem. The contaminated soil should no longer be used to grow food because the chemicals can leech into the food and harm people who eat it. The chemical fertilizer industry gives specific effect due to soil pollution. To determine ammonia and urea emissions from fertilizer industry, we can use physical characteristic of soil, which is magnetic susceptibility. Rock magnetism is used as a proxy indicator to determine changes in physical properties. Magnetic susceptibilities of samples in low and high frequency have been measured by Bartington MS2B magnetic susceptibility measurement device. The sample was taken from different area which located closer by pollution source and far from the pollution source. The susceptibility values of polluted samples in topsoil were quite low, with range from 187.1- 494.8 [x 10-8 m3 kg-1] when free polluted area’s sample has high values (1188.7- 2237.8 [x 10-8 m3 kg-1 ]). From this studies shows that susceptibility values in areas of the fertilizer industry are lower than the free polluted area.

Keywords: environmental, magnetic susceptibility, rock magnetism, soil pollution

Procedia PDF Downloads 335

Authors: Mustapha Sadouk

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This study investigates the sensitivity of high-frequency acoustic parameters in a rigid air-saturated porous bilayer material within the framework of the equivalent fluid theory, a specific case of the Biot model. The study specifically focuses on the sensitivity analysis in the frequency domain. The interaction between the fluid and solid phases of the porous medium incorporates visco-inertial and thermal exchange, characterized by two functions: the dynamic tortuosity α(ω) proposed by Johnson et al. and the dynamic compressibility β(ω) proposed by Allard, refined by Sadouki for the low-frequency domain of ultrasound. The parameters under investigation encompass porosity, tortuosity, viscous characteristic length, thermal characteristic length, as well as viscous and thermal shape factors. A +30% variation in these parameters is considered to assess their impact on the transmitted wave amplitudes. By employing this larger variation, a more comprehensive understanding of the sensitivity of these parameters is obtained. The outcomes of this study contribute to a better comprehension of the high-frequency wave behavior in porous bilayer materials, providing valuable insights for the design and optimization of such materials across various applications.

Keywords: bilayer materials, ultrasound, sensitivity analysis, equivalent fluid theory, dynamic tortuosity., porous material

Procedia PDF Downloads 65

Authors: Melahat Çevik

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The discovery of fabric has a quite old historical perspective because of veiling, heating and shelter needs of human. Since the days which fashion has a say, this situation has pasted beyond needs and has become status symbols. For the theater art drama which tell people by people, in the concern of reflecting daily life there will be such regards also we may see alternative products to artistically reshaped fabric. The stage is determined in the consensus of costume designer and director. Costume Designer does the research, taking into account the alternative products. Approaching nature as inventor, discovering products, shapes the work because in this work, cost is considerable. All types of fabric will be used but also new materials which are not presented to clothing industry yet are of great importance. In the discovery of new materials there priorities of the costume designer. In the scene everything should be determined in the axis of actor. The material discussed should have positive qualities which allow the performer to move and invigorate him or her in terms of physical and also should be positive in terms of health. This point must be approached in a more precise in high action plays and the obtained material should be tested before the presentation process.

Keywords: fabric, stage design, alternative materials, clothing industry

Procedia PDF Downloads 559

Authors: Chanho Park, Juneseok You, Kuewhan Jang, Sungsoo Na

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Detection technique of nanotoxic materials is strongly imperative, because nano-toxic materials can harmfully influence human health and environment as their engineering applications are growing rapidly in recent years. In present work, we report the DNA immobilized quartz crystal microbalance (QCM) based sensor for detection of nano-toxic materials such as silver ions, Hg2+ etc. by using functionalization of quartz crystal with a target-specific DNA. Since the mass of a target material is comparable to that of an atom, the mass change caused by target binding to DNA on the quartz crystal is so small that it is practically difficult to detect the ions at low concentrations. In our study, we have demonstrated fast and in situ detection of nanotoxic materials using quartz crystal microbalance. We report the label-free and highly sensitive detection of silver ion for present case, which is a typical nano-toxic material by using QCM and silver-specific DNA. The detection is based on the measurement of frequency shift of Quartz crystal from constitution of the cytosine-Ag+-cytosine binding. It is shown that the silver-specific DNA measured frequency shift by QCM enables the capturing of silver ions below 100pM. The results suggest that DNA-based detection opens a new avenue for the development of a practical water-testing sensor.

Keywords: nano-toxic ions, quartz crystal microbalance, frequency shift, target-specific DNA

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Authors: Jackson Ishara, Ariel Buzera, Gustave N. Mushagalusa, Ahmed R. A. Hammam, Judith Munga, Paul Karanja, John Kinyuru

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Numerous mushroom bioactive metabolites, including polysaccharides, eritadenine, lignin, chitosan, mevinolin, and astrakurkurone have been studied in life-threatening conditions and diseases such as diabetes, cardiovascular, hypertension, cancer, DNA damage, hypercholesterolemia, and obesity attempting to identify natural therapies. These bioactive metabolites have shown potential as antiviral and immune system strengthener natural agents through diverse cellular and physiological pathways modulation with no toxicity evidence, widely available, and affordable. In light of the emerging literature, this paper compiles the most recent information describing the molecular mechanisms that underlie the nutraceutical potentials of these mushroom metabolites suggesting their effectiveness if combined with existing drug therapies. The findings raise hope that these mushroom bioactive metabolites may be utilized as natural therapies considering their therapeutic potential while anticipating further research designing clinical trials and developing new drug therapies while encouraging their consumption as a natural adjuvant in preventing and controlling life-threatening conditions and diseases.

Keywords: bioactive metabolites, food functionality, health-threatening conditions, mushrooms, nutraceutical

Procedia PDF Downloads 86

Authors: Nurcan Tugrul, Funda Demir, Hilal Ozkan, Nur Olgun, Emek Derun

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Geopolymers are aluminosilicate-containing materials. The raw materials of the geopolymerization can be natural material such as kaolinite, metakaolin (calcined kaolinite), clay, diatomite, rock powder or can also be industrial by-products such as fly ash, silica fume, blast furnace slag, rice-husk ash, mine tailing, red mud, waste slag, etc. Reactivity of raw materials in geopolymer production is very important for achieving high reaction grade. Fly ash used in geopolymer production has been calcined to obtain tetrahedral SiO₂ and Al₂O₃ structures. In this study, fly ash calcined at different temperatures (700, 800 and 900 °C), and Al₂O₃ addition (Al₂O₃ at min (0%) and max (100%)) were used to produce geopolymers. HCl dissolution method was applied to determine the geopolymerization percentage of samples and Fourier Transform Infrared (FTIR) Spectroscopy was used to find out the optimum calcination temperature for geopolymerization. According to obtained results, the highest geopolymerization percentage (0% alumina added geopolymer equal to 35.789%; 100% alumina added geopolymer equal to 40.546%) was obtained in samples using fly ash calcined at 800 °C.

Keywords: geopolymer, fly ash, Al₂O₃ addition, calcination

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Authors: Donna M. Morrison, Lambert Chester, Coretta A. N. Samuels, David R. Ledoux

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A survey was conducted in the five rice-growing regions in Guyana to determine the presence of aflatoxins in multiple fractions of rice in June/October 2015 growing season. The fractions were paddy, steamed paddy, cargo rice, white rice and parboiled rice. Samples were analyzed by High Performance Liquid Chromatography. A subset of the samples was further analyzed by enzyme-linked immunosorbent assay (ELISA) for concurrence. All analyses were conducted at the University of Missouri, USA. Of the 186 samples tested, 16 had aflatoxin concentrations greater than 20 ppb the recommended limit for aflatoxins in food according to the United States Food and Drug Administration. An additional three samples had aflatoxin B₁ concentrations greater than the European Union Commission maximum levels for aflatoxin B₁ in rice at 5 µg/kg and total aflatoxins (B₁, B₂, G₁ and G₂) at 10 µg/kg. The survey indicates that there is no widespread aflatoxin problem in rice in Guyana. The incidence of aflatoxins appears to be localized.

Keywords: aflatoxin, enzyme-linked immunosorbent assay (ELISA), high-performance liquid chromatography (HPLC), rice fractions

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Authors: Daniela Rimnacova, Maryna Vorokhta, Martina Svabova

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CO₂ adsorption capacity of several materials - waste (power fly ash, slag, carbonized sewage sludge), rocks (Czech Silurian shale, black coal), and carbon (synthesized carbon, activated carbon as a reference material) - were measured on dry samples using a unique hand-made manometric sorption apparatus at a temperature of 45 °C and pressures of up to 7 MPa. The main aim was finding utilization of the waste materials and rocks for removal of the air or water pollutants caused by anthropogenic activities, as well as for the carbon dioxide storage. The equilibrium amount of the adsorbate depends on temperature, gas saturation pressure, porosity, surface area and volume of pores, and last but not least, on the composition of the adsorbents. Given experimental conditions can simulate in-situ situations in the rock bed and can be achieved just by a high-pressure apparatus. The CO₂ excess adsorption capacities ranged from 0.018 mmol/g (ash) to 13.55 mmol/g (synthesized carbon). The synthetized carbon had the highest adsorption capacity among all studied materials as well as the highest price. This material is usually used for the adsorption of specific pollutants. The excess adsorption capacity of activated carbon was 9.19 mmol/g. It is used for water and air cleaning. Ash can be used for chemisorption onto ash particle surfaces or capture of special pollutants. Shale is a potential material for enhanced gas recovery or CO₂ sequestration in-situ. Slag is a potential material for capture of gases with a possibility of the underground gas storage after the adsorption process. The carbonized sewage sludge is quite a good adsorbent for the removal and capture of pollutants, as well as shales or black coal which show an interesting relationship between the price and adsorption capacity.

Keywords: adsorption, CO₂, high pressure, porous materials

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Authors: Luqman Ali Shah, Murtaza Sayed, Mohammad Siddiq

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Three-dimensional cross-linked polymer microgels with temperature responsive N-isopropyl acrylamide (NIPAM) and pH-sensitive methacrylic acid (MAA) were successfully synthesized by free radical emulsion polymerization with different amount of MAA. Silver and gold nanoparticles with size of 6.5 and 3.5 nm (±0.5 nm) respectively were homogeneously reduced inside these materials by chemical reduction method at pH 2.78 and 8.36 for the preparation of hybrid materials. The samples were characterized by FTIR, DLS and TEM techniques. The catalytic activity of the hybrid materials was investigated for the reduction of 4-nitrophenol (4- NP) using NaBH4 as reducing agent by UV-visible spectroscopy. The hybrid polymer network synthesized at pH 8.36 shows enhanced catalytic efficiency compared to catalysts synthesized at pH 2.78. In this study, it has been explored that catalyst activity strongly depends on amount of MAA, synthesis pH and type of metal nanoparticles entrapped.

Keywords: cross-linked polymer microgels, free radical polymerization, metal nanoparticles, catalytic activity, comparative study

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Authors: Mike R. Bambach

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Increasing awareness of environmental concerns is leading a drive towards more sustainable structural products for the built environment. Natural fibres such as flax, jute and hemp have recently been considered for fibre-resin composites, with a major motivation for their implementation being their notable sustainability attributes. While recent decades have seen substantial interest in the use of such natural fibres in composite materials, much of this research has focused on the materials aspects, including fibre processing techniques, composite fabrication methodologies, matrix materials and their effects on the mechanical properties. The present study experimentally investigates the compression strength of structural channel sections of flax, jute and hemp, with a particular focus on their suitability for residential stud wall applications. The section geometry is optimised for maximum strength via the introduction of complex stiffeners in the webs and flanges. Experimental results on both natural fibre composite channel sections and typical steel and timber residential wall studs are compared. The geometrically optimised natural fibre composite channels are shown to have compression capacities suitable for residential wall stud applications, identifying them as a potentially viable alternative to traditional building materials in such application, and potentially other light structural applications.

Keywords: channel sections, natural fibre composites, residential stud walls, structural composites

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Authors: Lucas Viani, Benedetta Mennucci, Soo Young Park, Johannes Gierschner

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Organic semiconductors have attracted the attention of the scientific community in the past decades due to their unique physicochemical properties, allowing new designs and alternative device fabrication methods. Until today, organic electronic devices are largely based on conjugated polymers mainly due to their easy processability. In the recent years, due to moderate ET and CT efficiencies and the ill-defined nature of polymeric systems the focus has been shifting to small conjugated molecules with well-defined chemical structure, easier control of intermolecular packing, and enhanced CT and ET properties. It has led to the synthesis of new small molecules, followed by the growth of their crystalline structure and ultimately by the device preparation. This workflow is commonly followed without a clear knowledge of the ET and CT properties related mainly to the macroscopic systems, which may lead to financial and time losses, since not all materials will deliver the properties and efficiencies demanded by the current standards. In this work, we present a theoretical workflow designed to predict the key properties of ET of these new materials prior synthesis, thus speeding up the discovery of new promising materials. It is based on quantum mechanical, hybrid, and classical methodologies, starting from a single molecule structure, finishing with the prediction of its packing structure, and prediction of properties of interest such as static and averaged excitonic couplings, and exciton diffusion length.

Keywords: organic semiconductor, organic crystals, energy transport, excitonic couplings

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Authors: Małgorzata Golonka, Jadwiga Laska

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Self-healing polymers are one of the most investigated groups of smart materials. As materials engineering has recently focused on the design, production and research of modern materials and future technologies, researchers are looking for innovations in structural, construction and coating materials. Based on available scientific articles, it can be concluded that most of the research focuses on the self-healing of cement, concrete, asphalt and anticorrosion resin coatings. In our study, a method of obtaining and testing the properties of several types of microcapsules for use in self-healing polymer materials was developed. A method to obtain microcapsules exhibiting various mechanical properties, especially compressive strength was developed. The effect was achieved by using various polymer materials to build the shell: urea-formaldehyde resin (UFR), melamine-formaldehyde resin (MFR), melamine-urea-formaldehyde resin (MUFR). Dicyclopentadiene (DCPD) was used as the core material due to the possibility of its polymerization according to the ring-opening olefin metathesis (ROMP) mechanism in the presence of a solid Grubbs catalyst showing relatively high chemical and thermal stability. The ROMP of dicyclopentadiene leads to a polymer with high impact strength, high thermal resistance, good adhesion to other materials and good chemical and environmental resistance, so it is potentially a very promising candidate for the self-healing of materials. The capsules were obtained by condensation polymerization of formaldehyde with urea, melamine or copolymerization with urea and melamine in situ in water dispersion, with different molar ratios of formaldehyde, urea and melamine. The fineness of the organic phase dispersed in water, and consequently the size of the microcapsules, was regulated by the stirring speed. In all cases, to establish such synthesis conditions as to obtain capsules with appropriate mechanical strength. The microcapsules were characterized by determining the diameters and their distribution and measuring the shell thickness using digital optical microscopy and scanning electron microscopy, as well as confirming the presence of the active substance in the core by FTIR and SEM. Compression tests were performed to determine mechanical strength of the microcapsules. The highest repeatability of microcapsule properties was obtained for UFR resin, while the MFR resin had the best mechanical properties. The encapsulation efficiency of MFR was much lower compared to UFR, though. Therefore, capsules with a MUFR shell may be the optimal solution. The chemical reaction between the active substance present in the capsule core and the catalyst placed outside the capsules was confirmed by FTIR spectroscopy. The obtained autonomous repair systems (microcapsules + catalyst) were introduced into polyethylene in the extrusion process and tested for the self-repair of the material.

Keywords: autonomic self-healing system, dicyclopentadiene, melamine-urea-formaldehyde resin, microcapsules, thermoplastic materials

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Authors: M. S. Ashraf, Raja Rizwan Hussain, A. M. Alhozaimy, A. I. Al-Negheimish

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The effect of supplementary cementitious materials (SCMs) with concrete pore solution on the protective properties of the oxide films that form on reinforcing steel bars has been experimentally investigated using electrochemical impedance spectroscopy (EIS) and Tafel Scan. The tests were conducted on oxide films grown in saturated calcium hydroxide solutions that included different representative amounts of NaOH and KOH which are the compounds commonly observed in ordinary portland cement concrete pore solution. In addition to that, commonly used mineral admixtures (silica fume, natural pozzolan and fly ash) were also added to the simulated concrete pore solution. The results of electrochemical tests show that supplementary cementitious materials do have an effect on the protective properties of the passive oxide film. In particular, silica fume has been shown to have a negative influence on the film quality though it has positive effect on the concrete properties. Fly ash and natural pozzolan increase the protective qualities of the passive film. The research data in this area is very limited in the past and needed further investigation.

Keywords: supplementary cementitious materials (SCMs), passive film, EIS, Tafel scan, rebar, concrete, simulated concrete pore solution (SPS)

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Authors: EMMANUEL DWAMENA SASU

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International climate policy actions require countries under Paris Agreement to design instruments, provide support (financial and technical), and strengthen institutional capacity with tendency to transcending policy formulation to implementation and sustainability. Changes associated with moisture depletion has been a growing phenomenon; especially in developing countries with projected global GDP drop from 7% to 2% between 2005 and 2050. These developments have potential to adversely affect food production in feeding the growing world population, with corresponding rise in global hunger. Incongruously, there is global absence of a harmonized policy direction; capable of providing the required indicators on climate policies for monitoring sustainability of international agricultural development projects. We conduct extensive review and synthesis on existing limitations on global climate policy governance, agricultural food security and sustainability of international agricultural development projects, and conjecture the role of non-state and sub-national climate stakeholder engagements, and monitoring and evaluation strategies for improved climate policy action for sustaining international agricultural development projects.

Keywords: climate policy, agriculture, development projects, sustainability

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Authors: Pontsho E. Tseke, Phatu W. Mashela

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Climate-smart agriculture dictates that underusilised indigenous plant, which served as food for local marginalized communities, be assessed for introduction into mainstream agriculture. Most of the underutilised indigenous plants had survived adverse conditions in the wild; with limited information on how the interact with most abiotic and biotic factors. Cucumis myriocarpus leafy vegetable has nutritional, pharmacological and industrial applications, with limited information on how it interacts with effective microorganisms. The objective of this study was to determine the effects vesicular arbuscular mycorrhiza (VAM) on the growth of C. myriocarpus indigenous leafy vegetable under greenhouse conditions. Four-weeks-old seedlings of C. myriocarpus were transplanted into 20-cm-diameter plastic pots. Two weeks after transplanting, VAM was applied at 0, 10, 20, 30, 40, 50, 60 and 70 g Biocult-VAM plant. At 56 days after treatments, plant growth variables of C. myriocarpus with increase Biocult-VAM levels exhibited positive quadratic relations. Plant variables and increasing concentrations of salinity exhibited positive quadric relations, with 95 to 99% associations. Inclusion, Biocult-VAM can be used in sustainable production of C. myriocarpus for functional food security.

Keywords: abiotic, biotic, rhizasphere, sustainable agriculture

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Authors: C. E. Ogbanje, S. A. N. D. Chidebelu, N. J. Nweze

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The study evaluated off-farm work and cost efficiency in staple food production among small-scale farmers in North Central Nigeria. Multistage sampling technique was used to select 360 respondents (participants and non-participants in off-farm work). Primary data obtained were analysed using stochastic cost frontier and test of means’ difference. Capital input was lower for participants (N2,596.58) than non-participants (N11,099.14). Gamma (γ) was statistically significant. Farm size significantly (p<0.01) increased cost outlay for participants and non-participants. Average input prices of enterprises one and two significantly (p<0.01) increased cost. Sex, household size, credit obtained, formal education, farming experience, and farm income significantly (p<0.05) reduced cost inefficiency for non-participants. Average cost efficiency was 11%. Farm capital was wasted. Participants’ substitution of capital for labour did not put them at a disadvantage. Extension agents should encourage farmers to obtain financial relief from off-farm work but not to the extent of endangering farm cost efficiency.

Keywords: cost efficiency, mean difference, North Central Nigeria, off-farm work, participants and non-participants, small-scale farmers

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Authors: Anastasia Stamatiou, Melissa Obermeyer, Ludger J. Fischer, Philipp Schuetz, Jörg Worlitschek

Abstract:

This study evaluates unbranched, saturated carboxylic esters with respect to their suitability to be used as storage media for latent heat storage applications. Important thermophysical properties are gathered both by means of literature research as well as by experimental measurements. Additionally, esters are critically evaluated against other common phase-change materials in terms of their environmental impact and their economic potential. The experimental investigations are performed for eleven selected ester samples with a focus on the determination of their melting temperature and their enthalpy of fusion using differential scanning calorimetry. Transient Hot Bridge was used to determine the thermal conductivity of the liquid samples while thermogravimetric analysis was employed for the evaluation of the 5% weight loss temperature as well as of the decomposition temperature of the non-volatile samples. Both experimental results and literature data reveal the high potential of esters as phase-change materials. Their good thermal and environmental properties as well as the possibility for production from natural sources (e.g. vegetable oils) render esters as very promising for future storage applications. A particularly high short term application potential of esters could lie in low temperature storage applications where the main alternative is using salt hydrates as phase-change material.

Keywords: esters, phase-change materials, thermal properties, latent heat storage

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Authors: Hadas Hirsch

Abstract:

Clothing is aimed at concealing and revealing the body, protecting it, and manifesting religious, political, and social declarations. The material and symbolic meanings of clothing and its raw materials are evaluated through the context of their social, cultural, and religious systems. The raw materials for clothing that were frequent and familiar in the 7th century Arab Peninsula were wool, leather, cotton, and some kinds of silk. The spread of the Muslim empire and the intersections with other religions and cultures enable the trickling of new raw materials that were unknown to Muslims or unaccepted. The sources for this research are hadith collections that discuss in details various kinds of textiles and their origin, together with a legal explanation that permits or prohibits its use. The paper will describe and analyze this discussion by contextualizing it in social, religious, and cultural reality that creates a structure of socio-religious dependency. The aim is not to identify, catalogue, and technically analyze fabrics but to reveal their role in Muslims’ life as a means of creating dependency for the community and setting borders inside and outside. The analysis is built upon a scale that starts with the most recommended raw materials, then comes the permitted ones and, in the end, the prohibited raw materials. This mapping will provide an insight into the ways textiles, as a cultural medium, help to shape and redefine identities and, at the same time, enable a sphere for creative expression within socio-cultural and religious limits and context. To sum up, hadith literature has the main role is characterizing Muslim clothing, from garments to textiles and colors, including multiple variations and contradicting aspects. The Muslim style of clothing and, in particular, textiles is a manifestation of the socio-religious structure of dependency that creates differentiated Muslim identity together with subdivision of gendered groups. Some other aspects are the tension between authenticity and imitation and the jurists’ pragmatic and practice attitude that enables an individual sphere of expression within the limits of jurisprudence.

Keywords: Hadith, jurisprudence, medieval Islam, material culture

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Authors: Mohammed Alghamdi, Ghanem Al-Ghamdi

Abstract:

The Governorate of Al-Baha is known for a history of farming that focused on plant products such as Date Palm, olives, figs, pomegranate and cereals as well as raising cattle, sheep, goats and to some extent camels for many decades. However, farmers have been facing with very significant natural and artificial challenges lately. The goal of this study was to determine the most significant challenges facing farmers in the Governorate of Al-Baha. Sixty farms were surveyed during the year of 2013. Farm survey focused on the farm management, farm financial status and governmental support. Our results showed that most farms were dedicated to farming with limited number of farms used parts of its premises for recreation. About 90% of farms were engaged in exclusively farming business. The financial status was good in most of the farms (80%), stable in 16% and hardly standing in less than 5%. Nearly 60% of the farms marketed 1-3 products and 23% marketed up to 6 products, 14% of the farms marketed up to 9 products and 4% marketed more than 9 products. Less than 14% had a chance to market their products over seven times per year while about 11% market their products and 32% of farms market 3-4 per year and 43% of farms market 1-2 per year. Our data showed that most farmers are in good financial status producing healthy food.

Keywords: farming system, Al-Baha, healthy food, Saudi Arabia

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Authors: Wasiu Oyeleke Oyediran

Abstract:

Maize is a common staple food for human consumption and livestock feeds. It provides employment and means of livelihood for women in both rural areas and urban centres in Nigeria. However, the entrepreneurial skills of women engaged in its processing and value addition has not been fully enhanced. This study was therefore carried out to investigate rural women entrepreneurial skills in maize processing and value addition in Ogun State, Nigeria. Snow ball sampling technique was used in the selection of 70 respondents for this study. Data were analyzed with descriptive statistics and chi-square. Results revealed that majority (50.0%) of the respondents were 31 - 40 years of age and 60% of the respondents had spent 6 – 10 years in maize processing. The respondents have great entrepreneurial skills in popcorn (85.7%), corn cake (80.0%), corn balls (64.3%) and kokoro (52.9%) making. The majority of the respondents accessed information and entrepreneurial skills through fellow processors (88.6%) and friends and neighbours (62.9%). Major constraints to maize processing and value addition were scarcity of raw materials during off season periods (95.7%), ineffective preservation methods (88.6%), lack of modern processing equipment (82.9%), and high cost of processing machines (72.9%). Result of chi-square showed that there is significant association between personal characteristics of the respondents and entrepreneurial skills of the women at p < 0.05. It is hereby recommended that subsidized processing equipment should be made available to the maize processors in the study area by the government and NGOs.

Keywords: women, entreprenuerial skills, maize prcessing, value addition

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Authors: N. AlShaya, R. Alhomidan, S. Alromizan, W. Labib

Abstract:

Plant-based natural fibers are used more increasingly in construction materials. It is done to reduce the pressure on the built environment, which has been increased dramatically due to the increases world population and their needs. Plant-based natural fibers are abundant in many countries. Despite the low-cost of such environmental friendly renewable material, it has the ability to enhance the mechanical properties of construction materials. This paper presents an extensive discussion on the use of plant-based natural fibers as reinforcement for cement-based composites, with a particular emphasis upon fiber types; fiber characteristics, and fiber-cement composites performance. It also covers a thorough overview on the main factors, affecting the properties of plant-based natural fiber cement composite in it fresh and hardened state. The feasibility of using plant-based natural fibers in producing various construction materials; such as, mud bricks and blocks is investigated. In addition, other applications of using such fibers as internal curing agents as well as durability enhancer are also discussed. Finally, recommendation for possible future work in this area is presented.

Keywords: natural fibres, cement composites, construction materia, sustainability, stregth, durability

Procedia PDF Downloads 206