Search results for: mechanism properties
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 11547

Search results for: mechanism properties

2307 Extracellular Enzymes as Promising Soil Health Indicators: Assessing Response to Different Land Uses Using Long-Term Experiments

Authors: Munisath Khandoker, Stephan Haefele, Andy Gregory

Abstract:

Extracellular enzymes play a key role in soil organic carbon (SOC) decomposition and nutrient cycling and are known indicators for soil health; however, it is not understood how these enzymes respond to different land uses and their relationships to other soil properties have not been extensively reviewed. The relationships among the activities of three soil enzymes: β-glucosaminidase (NAG), phosphomonoesterase (PHO) and β-glucosidase (GLU), were examined. The impact of soil organic amendments, soil types and land management on soil enzyme activities were reviewed, and it was hypothesized that soils with increased SOC have increased enzyme activity. Long-term experiments at Rothamsted Research Woburn and Harpenden sites in the UK were used to evaluate how different management practices affect enzyme activity involved in carbon (C) and nitrogen (N) cycling in the soil. Samples were collected from soils with different organic treatments such as straw, farmyard manure (FYM), compost additions, cover crops and permanent grass cover to assess whether SOC can be linked with increased levels of enzymatic activity and what influence, if any, enzymatic activity has on total C and N in the soil. Investigating the interactions of important enzymes with soil characteristics and SOC can help to better understand the health of soils. Studies on long-term experiments with known histories and large datasets can better help with this. SOC tends to decrease during land use changes from natural ecosystems to agricultural systems; therefore, it is imperative that agricultural lands find ways to increase and/or maintain SOC in the soil.

Keywords: biological soil health indicators, extracellular enzymes, soil health, soil, microbiology

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2306 Synthesis and Characterization of an Aerogel Based on Graphene Oxide and Polyethylene Glycol

Authors: Javiera Poblete, Fernando Gajardo, Katherina Fernandez

Abstract:

Graphene, and its derivatives such as graphene oxide (GO), are emerging nanoscopic materials, with interesting physical and chemical properties. From them, it is possible to develop three-dimensional macrostructures, such as aerogels, which are characterized by a low density, high porosity, and large surface area, having a promising structure for the development of materials. The use of GO as a precursor of these structures provides a wide variety of materials, which can be developed as a result of the functionalization of their oxygenated groups, with specific compounds such as polyethylene glycol (PEG). The synthesis of aerogels of GO-PEG for non-covalent interactions has not yet been widely reported, being of interest due to its feasible escalation and economic viability. Thus, this work aims to develop a non-covalently functionalized GO-PEG aerogels and characterize them physicochemically. In order to get this, the GO was synthesized from the modified hummers method and it was functionalized with the PEG by polymer-assisted GO gelation (crosslinker). The gelation was obtained for GO solutions (10 mg/mL) with the incorporation of PEG in different proportions by weight. The hydrogel resulting from the reaction was subsequently lyophilized, to obtain the respective aerogel. The material obtained was chemically characterized by analysis of Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray diffraction (XRD), and its morphology by scanning electron microscopy (SEM) images; as well as water absorption tests. The results obtained showed the formation of a non-covalent aerogel (FTIR), whose structure was highly porous (SEM) and with a water absorption values greater than 50% g/g. Thus, a methodology of synthesis for GO-PEG was developed and validated.

Keywords: aerogel, graphene oxide, polyethylene glycol, synthesis

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2305 Investigation of Physical Performance of Denim Fabrics Washed with Sustainable Foam Washing Process

Authors: Hazal Yılmaz, Hale Karakaş

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In the scope of the study, it is aimed to investigate and review the performance of denim fabrics that are foam washed. Foam washing was compared as an alternative to stone washing in terms of sustainability and performance parameters. For this purpose, seven different denim fabrics, which are both stone washed and foam washed separately in 3 different washing durations (30-60-90 mins), were compared. In the study, the same fabrics were processed with both foam and stone separately. The washing process steps were reviewed, and their water consumption values were compared. After washing, a total of 42 fabric samples were obtained, and tensile strength, tear strength, abrasion, weight loss after abrasion, rubbing fastness, color fastness tests were carried out on the fabric samples. The obtained test results were reviewed and evaluated. As a result of tests, it has been observed that the performance of foam washed fabrics in terms of tensile, tear strength and rubbing fastness test results are better than stone washed fabrics, and it has been seen that foam washed fabrics' color fastness test results are as stone washed. As a result of all these tests, it can be seen that foam washing is an alternative to stone washing due to its performance parameters and its sustainability performance with less water usage.

Keywords: denim fabrics, denim washing, foam washing, performance properties, stone washing, sustainability

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2304 Active Abdominal Compression Device for Treatment of Orthostatic Hypotension

Authors: Vishnu Emani, Andreas Escher, Ellen Roche

Abstract:

Background: Orthostatic hypotension (OH) is an autonomic disorder marked by a sudden drop in blood pressure upon standing resulting from autonomic dysfunction. OH is especially prevalent in elderly populations, affecting more than 30% of Americans over the age of 70. OH is one of the most significant risk factors for accidental falls in elderly populations, making it a crucial focus for medical and device therapies. Pharmacologic therapy with midodrine and fludrocortisone may alleviate hypotension but have significant adverse side effects. Abdominal passive compression devices (binders) are more effective than lower extremity compression stockings at mitigating postural hypotension, by improving venous return to the heart. However, abdominal binders are difficult to don and uncomfortable to wear, leading to poor compliance. A disadvantage of passive compression devices is their inability to selectively compress during the crucial moment of standing. it have recently developed an active compression device that applies external pressure on the abdomen during transition from prone to supine position and conducted initial prototype testing. Methods: An active abdominal compression device was developed utilizing a simple, servo-driven strap-tightening mechanism to supply tension onto foam fabric, which applies pressure to the abdomen. Healthy volunteers (n=5) were utilized for prototype testing and were subjected to three conditions: no compression, passive compression (i.e. standard abdominal binder), and active compression (device prototype). Abdominal applied pressure during device activation was measured by strain-gauge manometer placed between the skin and binder. Systolic (SBP) and mean (MAP) arterial blood pressure was measured by standard blood pressure cuff in supine position followed by repeat measurements at 1 minute intervals for 5 minutes following upright position. A survey tool was administered to determine scores (1-10) for comfort and ease of donning abdominal binders. Results: Abdominal pressure increased from 0 to 15±3 mmHg upon device activation for both passive and active compression devices. During transition from supine to upright position, both active and passive compression devices demonstrated significantly higher MAP compared to the no-compression condition (67±4, 68±5, 62±5 respectively P<0.05), but there was no statistically significant difference in SBP or MAP when comparing active to passive compression. Active compression demonstrated significantly higher comfort scores (8.3±1) compared to passive compression (3.2±2) but lower when compared to no compression (10). Subjects universally reported that active compression device was easier to don compared to passive device. Conclusions: Active or passive abdominal compression prevents hypotension associated with postural changes. Active compression is associated with increased comfort and ease of donning compared to passive compression devices. Future trials are warranted to investigate the efficacy of our device in patients with OH.

Keywords: orthostatic hypotension, compression binder, abdominal binder, active abdominal compression

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2303 Glutharaldyde Free Processing of Patch for Cardiovascular Repair Is Associated with Improved Outcomes on Rvot Repair, Rat Model

Authors: Parnaz Boodagh, Danila Vella, Antonio Damore, Laura Modica De Mohac, Sang-Ho Ye, Garret Coyan, Gaetano Burriesci, William Wagner, Federica Cosentino

Abstract:

The use of cardiac patches is among the main therapeutic solution for cardiovascular diseases, a leading mortality cause in the world with an increasing trend, responsible of 19 millions deaths in 2020. Several classes of biomaterials serve that purpose, both of synthetic origin and biological derivation, and many bioengineered treatment alternatives were proposed to satisfy two main requirements, providing structural support and promoting tissue remodeling. The objective of this paper is to compare the mechanical properties and the characterization of four cardiac patches: the Adeka, PhotoFix, CorPatch, and CardioCel patches. In vitro and in vivo tests included: biaxial, uniaxial, ball burst, suture retention for mechanical characterization; 2D surface topography, 3D volume and microstructure, and histology assessments for structure characterization; in vitro test to evaluate platelet deposition, calcium deposition, and macrophage polarization; rat right ventricular outflow tract (RVOT) models at 8- and 16-week time points to characterize the patch-host interaction. Lastly, the four patches were used to produce four stented aortic valve prosthesis, subjected to hydrodynamic assessment as well as durability testing to verify compliance with the standard ISO.

Keywords: cardiac patch, cardiovascular disease, cardiac repair, blood contact biomaterial

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2302 Intestine Characteristics and Blood Profile of Broiler Chickens Treated with Garlic

Authors: Mary Anthony Oguike, Ilouno, Amaduruonye

Abstract:

A completely randomized design experiment with 3 treatments was conducted to study the effects of garlic on intestine characteristics, haematology and serum biochemistry of Marshal broilers. Thirty three (33) broiler chicks were randomly allotted to each treatment designated T1, T2 and T3. The birds in each treatment were replicated 3 times with 11 broilers per replicate. They were fed diets supplemented with garlic at 0, 1.5 and 2.5 % /kg feed for t1, T2 and T3, respectively with T1 as control. Data were collected on intestine parameters, serum biochemical parameters and haematological indices. The results showed significant (P>0.05) dose-dependent decrease in intestine weight and caeca microbial load of the broilers. The intestine of broilers in the treatments showed normal histological architecture in all the treatments. The red blood cell (RBC), white blood cell (WBC), haemoglobin (Hb) and other haematological indices showed no significant differences (P<0.05) among the treatments. Cholesterol, globulin, glucose and alanin aminotransferase (ALT) were significantly different (P<0.05) among the treatment groups. Serum biochemical parameters such as, total protein albumin, bilirubin and others were not significant among the treatments. All the blood parameters studied fall within the normal range for broilers. Garlic supplementation in the diets of broilers did not have any detrimental effects on the treated birds since their serum biochemistry and haematology fall within the normal range for broilers birds. The microbial examination of intestine and caeca, as well as the histopathological studies of the intestine confirmed antimicrobial properties of garlic.

Keywords: broiler, biochemistry and haematology, garlic, intestine

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2301 Traditional Women's Clothes at Tekirdağ Region

Authors: E. Elhan Özus, Melek Tufan, Filiz Erden

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Cloth is a special wearing style of a society for a period or of a profession. Clothes reflect the social status difference than the fashion. Within this context, society forms a wearing style in the direction of its customs, usage, traditions and social structure. One of the properties of a society indicating the social levels and cultural differences differing the societies from each other is clothing style. Clothing is one of the most important needs in life depending on the individual and social attributes. The clothing which first emerged as protection means is a social fact complementing the physical and psychological existence of human being, changing forms depending on technological developments and phases, and continuously changing under the affect of fashion today. Clothing is an aesthetic value fed by the feelings of individuals. So, clothing has an indispensable place in the structure and communication of cultural and social identity within this direction. The traditional Turkish clothing has a rich ethnography. It is also possible to see the winds coming from our predecessors in these cultural assets reflecting the feelings and thoughts of Anatolian women. When the long history of our nation and the cultures interacted by our nation are taken into account, it is seen that the magnificence of our nation has also reflected into the clothing culture.For this reason, we tried to keep the traditional women’s clothing of Tekirdağ region alive by investigating and documenting them. In this study, it is purposed to contribute a little bit to protect our culture and form a source for the future generations, to carry our national cultural values from the past up to now and to the future and deliver to the young people.

Keywords: Turkish, traditional, culture, clothing

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2300 Prediction of Distillation Curve and Reid Vapor Pressure of Dual-Alcohol Gasoline Blends Using Artificial Neural Network for the Determination of Fuel Performance

Authors: Leonard D. Agana, Wendell Ace Dela Cruz, Arjan C. Lingaya, Bonifacio T. Doma Jr.

Abstract:

The purpose of this paper is to study the predict the fuel performance parameters, which include drivability index (DI), vapor lock index (VLI), and vapor lock potential using distillation curve and Reid vapor pressure (RVP) of dual alcohol-gasoline fuel blends. Distillation curve and Reid vapor pressure were predicted using artificial neural networks (ANN) with macroscopic properties such as boiling points, RVP, and molecular weights as the input layers. The ANN consists of 5 hidden layers and was trained using Bayesian regularization. The training mean square error (MSE) and R-value for the ANN of RVP are 91.4113 and 0.9151, respectively, while the training MSE and R-value for the distillation curve are 33.4867 and 0.9927. Fuel performance analysis of the dual alcohol–gasoline blends indicated that highly volatile gasoline blended with dual alcohols results in non-compliant fuel blends with D4814 standard. Mixtures of low-volatile gasoline and 10% methanol or 10% ethanol can still be blended with up to 10% C3 and C4 alcohols. Intermediate volatile gasoline containing 10% methanol or 10% ethanol can still be blended with C3 and C4 alcohols that have low RVPs, such as 1-propanol, 1-butanol, 2-butanol, and i-butanol. Biography: Graduate School of Chemical, Biological, and Materials Engineering and Sciences, Mapua University, Muralla St., Intramuros, Manila, 1002, Philippines

Keywords: dual alcohol-gasoline blends, distillation curve, machine learning, reid vapor pressure

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2299 Effect of Fat Percentage and Prebiotic Composition on Proteolysis, ACE-Inhibitory and Antioxidant Activity of Probiotic Yogurt

Authors: Mohammad B. HabibiNajafi, Saeideh Sadat Fatemizadeh, Maryam Tavakoli

Abstract:

In recent years, the consumption of functional foods, including foods containing probiotic bacteria, has come to notice. Milk proteins have been identified as a source of angiotensin-I-converting enzyme )ACE( inhibitory peptides and are currently the best-known class of bioactive peptides. In this study, the effects of adding prebiotic ingredients (inulin and wheat fiber) and fat percentage (0%, 2% and 3.5%) in yogurt containing probiotic Lactobacillus casei on physicochemical properties, degree of proteolysis, antioxidant and ACE-inhibitory activity within 21 days of storage at 5 ± 1 °C were evaluated. The results of statistical analysis showed that the application of prebiotic compounds led to a significant increase in water holding capacity, proteolysis and ACE-inhibitory of samples. The degree of proteolysis in yogurt increases as storage time elapses (P < 0.05) but when proteolysis exceeds a certain threshold, this trend begins to decline. Also, during storage time, water holding capacity reduced initially but increased thereafter. Moreover, based on our findings, the survival of Lactobacillus casei in samples treated with inulin and wheat fiber increased significantly in comparison to the control sample (P < 0.05) whereas the effect of fat percentage on the survival of probiotic bacteria was not significant (P = 0.095). Furthermore, the effect of prebiotic ingredients and the presence of probiotic cultures on the antioxidant activity of samples was significant (P < 0.05).

Keywords: probiotic yogurt, proteolysis, ACE-inhibitory, antioxidant activity

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2298 Collaboration between Grower and Research Organisations as a Mechanism to Improve Water Efficiency in Irrigated Agriculture

Authors: Sarah J. C. Slabbert

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The uptake of research as part of the diffusion or adoption of innovation by practitioners, whether individuals or organisations, has been a popular topic in agricultural development studies for many decades. In the classical, linear model of innovation theory, the innovation originates from an expert source such as a state-supported research organisation or academic institution. The changing context of agriculture led to the development of the agricultural innovation systems model, which recognizes innovation as a complex interaction between individuals and organisations, which include private industry and collective action organisations. In terms of this model, an innovation can be developed and adopted without any input or intervention from a state or parastatal research organisation. This evolution in the diffusion of agricultural innovation has put forward new challenges for state or parastatal research organisations, which have to demonstrate the impact of their research to the legislature or a regulatory authority: Unless the organisation and the research it produces cross the knowledge paths of the intended audience, there will be no awareness, no uptake and certainly no impact. It is therefore critical for such a research organisation to base its communication strategy on a thorough understanding of the knowledge needs, information sources and knowledge networks of the intended target audience. In 2016, the South African Water Research Commission (WRC) commissioned a study to investigate the knowledge needs, information sources and knowledge networks of Water User Associations and commercial irrigators with the aim of improving uptake of its research on efficient water use in irrigation. The first phase of the study comprised face-to-face interviews with the CEOs and Board Chairs of four Water User Associations along the Orange River in South Africa, and 36 commercial irrigation farmers from the same four irrigation schemes. Intermediaries who act as knowledge conduits to the Water User Associations and the irrigators were identified and 20 of them were subsequently interviewed telephonically. The study found that irrigators interact regularly with grower organisations such as SATI (South African Table Grape Industry) and SAPPA (South African Pecan Nut Association) and that they perceive these organisations as credible, trustworthy and reliable, within their limitations. State and parastatal research institutions, on the other hand, are associated with a range of negative attributes. As a result, the awareness of, and interest in, the WRC and its research on water use efficiency in irrigated agriculture are low. The findings suggest that a communication strategy that involves collaboration with these grower organisations would empower the WRC to participate much more efficiently and with greater impact in agricultural innovation networks. The paper will elaborate on the findings and discuss partnering frameworks and opportunities to manage perceptions and uptake.

Keywords: agricultural innovation systems, communication strategy, diffusion of innovation, irrigated agriculture, knowledge paths, research organisations, target audiences, water use efficiency

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2297 Synthesis of Modified Cellulose for the Capture of Uranyl Ions from Aqueous Solutions

Authors: Claudia Vergara, Oscar Valdes, Jaime Tapia, Leonardo Santos

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The poly(amidoamine) dendrimers (PAMAM) are a class of material introduced by D. Tomalia. Modifications of the PAMAM dendrimer with several functional groups have attracted the attention for new interesting properties and new applications in many fields such as chemistry, physics, biology, and medicine. However, in the last few years, the use of dendrimers in environmental applications has increased due to pollution concerns. In this contribution, we report the synthesis of three new PAMAM derivates modified with asparagine aminoacid supported in cellulose: PG0-Asn (PAMAM-asparagine), PG0-Asn-Trt (with trityl group) and PG0-Asn-Boc-Trt (with tert-butyl oxycarbonyl group). The functionalization of generation 0 PAMAM dendrimer was carried out by amidation reaction by using an EDC/HOBt protocol. In a second step, functionalized dendrimer was covalently supported to the cellulose surface and used to study the capture of uranyl ions from aqueous solution by fluorescence spectroscopy. The structure and purity of the desired products were confirmed by conventional techniques such as FT-IR, MALDI, elemental analysis, and ESI-MS. Batch experiments were carried out to determine the affinity of uranyl ions with the dendrimer in aqueous solution. Firstly, the optimal conditions for uranyl capture were obtained, where the optimum pH for the removal was 6, the contact time was 4 hours, the initial concentration of uranyl was 100 ppm, and the amount of the adsorbent to be used was 2.5 mg. PAMAM significantly increased the capture of uranyl ions with respect to cellulose as the starting substrate, reaching 94.8% of capture (PG0), followed by 91.2% corresponding to PG0-Asn-Trt, then 70.3% PG0-Asn and 24.2% PG0-Asn-Boc-Trt. These results show that the PAMAM dendrimer is a good option to remove uranyl ions from aqueous solutions.

Keywords: asparagine, cellulose, PAMAM dendrimer, uranyl ions

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2296 Persistent Ribosomal In-Frame Mis-Translation of Stop Codons as Amino Acids in Multiple Open Reading Frames of a Human Long Non-Coding RNA

Authors: Leonard Lipovich, Pattaraporn Thepsuwan, Anton-Scott Goustin, Juan Cai, Donghong Ju, James B. Brown

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Two-thirds of human genes do not encode any known proteins. Aside from long non-coding RNA (lncRNA) genes with recently-discovered functions, the ~40,000 non-protein-coding human genes remain poorly understood, and a role for their transcripts as de-facto unconventional messenger RNAs has not been formally excluded. Ribosome profiling (Riboseq) predicts translational potential, but without independent evidence of proteins from lncRNA open reading frames (ORFs), ribosome binding of lncRNAs does not prove translation. Previously, we mass-spectrometrically documented translation of specific lncRNAs in human K562 and GM12878 cells. We now examined lncRNA translation in human MCF7 cells, integrating strand-specific Illumina RNAseq, Riboseq, and deep mass spectrometry in biological quadruplicates performed at two core facilities (BGI, China; City of Hope, USA). We excluded known-protein matches. UCSC Genome Browser-assisted manual annotation of imperfect (tryptic-digest-peptides)-to-(lncRNA-three-frame-translations) alignments revealed three peptides hypothetically explicable by 'stop-to-nonstop' in-frame replacement of stop codons by amino acids in two ORFs of the lncRNA MMP24-AS1. To search for this phenomenon genomewide, we designed and implemented a novel pipeline, matching tryptic-digest spectra to wildcard-instead-of-stop versions of repeat-masked, six-frame, whole-genome translations. Along with singleton putative stop-to-nonstop events affecting four other lncRNAs, we identified 24 additional peptides with stop-to-nonstop in-frame substitutions from multiple positive-strand MMP24-AS1 ORFs. Only UAG and UGA, never UAA, stop codons were impacted. All MMP24-AS1-matching spectra met the same significance thresholds as high-confidence known-protein signatures. Targeted resequencing of MMP24-AS1 genomic DNA and cDNA from the same samples did not reveal any mutations, polymorphisms, or sequencing-detectable RNA editing. This unprecedented apparent gene-specific violation of the genetic code highlights the importance of matching peptides to whole-genome, not known-genes-only, ORFs in mass-spectrometry workflows, and suggests a new mechanism enhancing the combinatorial complexity of the proteome. Funding: NIH Director’s New Innovator Award 1DP2-CA196375 to LL.

Keywords: genetic code, lncRNA, long non-coding RNA, mass spectrometry, proteogenomics, ribo-seq, ribosome, RNAseq

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2295 The Effect of Linear Low-Density Polyethylene Cross-Contamination by Other Plastic Types on Bitumen Modification

Authors: Nioushasadat Haji Seyed Javadi, Ailar Hajimohammadi, Nasser Khalili

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Currently, the recycling of plastic wastes has been the subject of much research attention, especially in pavement constructions, where virgin polymers can be replaced by recycled plastics for asphalt binder modification. Among the plastic types, recycled linear low-density polyethylene (RLLDPE) has been one of the common and largely available plastics for bitumen modification. However, it is important to note that during the recycling process, LLDPE can easily be contaminated with other plastic types, especially with low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP). The cross-contamination of LLDPE with other plastics lowers its quality and, consequently, can affect the asphalt modification process. This study aims to assess the effect of LLDPE cross-contamination on bitumen modification. To do so, samples of bitumen modified with LLDPE and blends of LLDPE with LDPE, HDPE, and PP were prepared and compared through physical and rheological evaluations. The experimental tests, including softening point, penetration, viscosity at 135 °C, and dynamic shear rheometer, were conducted. The results indicated that the effect of cross-contamination on softening point and rutting resistance was negligible. On the other side, penetration and viscosity were highly impacted. The results also showed that among contamination of LLDPE with the other plastic types, PP had the highest influence in comparison with HDPE and LDPE on changing the properties of the LLDPE- modified bitumen.

Keywords: recycled polyethylene, polymer cross-contamination, waste plastic, bitumen, rutting resistance

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2294 The Effect of Crack Size, Orientation and Number on the Elastic Modulus of a Cracked Body

Authors: Mark T. Hanson, Alan T. Varughese

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Osteoporosis is a disease affecting bone quality which in turn can increase the risk of low energy fractures. Treatment of osteoporosis using Bisphosphonates has the beneficial effect of increasing bone mass while at the same time has been linked to the formation of atypical femoral fractures. This has led to the increased study of micro-fractures in bones of patients using Bisphosphonate treatment. One of the mechanics related issues which have been identified in this regard is the loss in stiffness of bones containing one or many micro-fractures. Different theories have been put forth using fracture mechanics to determine the effect of crack presence on elastic properties such as modulus. However, validation of these results in a deterministic way has not been forthcoming. The present analysis seeks to provide this deterministic evaluation of fracture’s effect on the elastic modulus. In particular, the effect of crack size, crack orientation and crack number on elastic modulus is investigated. In particular, the Finite Element method is used to explicitly determine the elastic modulus reduction caused by the presence of cracks in a representative volume element. Single cracks of various lengths and orientations are examined as well as cases of multiple cracks. Cracks in tension as well as under shear stress are considered. Although the focus is predominantly two-dimensional, some three-dimensional results are also presented. The results obtained show the explicit reduction in modulus caused by the parameters of crack size, orientation and number noted above. The present results allow the interpretation of the various theories which currently exist in the literature.

Keywords: cracks, elastic, fracture, modulus

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2293 From Talk to Action-Tackling Africa’s Pollution and Climate Change Problem

Authors: Ngabirano Levis

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One of Africa’s major environmental challenges remains air pollution. In 2017, UNICEF estimated over 400,000 children in Africa died as a result of indoor pollution, while 350 million children remain exposed to the risks of indoor pollution due to the use of biomass and burning of wood for cooking. Over time, indeed, the major causes of mortality across Africa are shifting from the unsafe water, poor sanitation, and malnutrition to the ambient and household indoor pollution, and greenhouse gas (GHG) emissions remain a key factor in this. In addition, studies by the OECD estimated that the economic cost of premature deaths due to Ambient Particulate Matter Pollution (APMP) and Household Air Pollution across Africa in 2013 was about 215 Billion US Dollars and US 232 Billion US Dollars, respectively. This is not only a huge cost for a continent where over 41% of the Sub-Saharan population lives on less than 1.9 US Dollars a day but also makes the people extremely vulnerable to the negative climate change and environmental degradation effects. Such impacts have led to extended droughts, flooding, health complications, and reduced crop yields hence food insecurity. Climate change, therefore, poses a threat to global targets like poverty reduction, health, and famine. Despite efforts towards mitigation, air contributors like carbon dioxide emissions are on a generally upward trajectory across Africa. In Egypt, for instance, emission levels had increased by over 141% in 2010 from the 1990 baseline. Efforts like the climate change adaptation and mitigation financing have also hit obstacles on the continent. The International Community and developed nations stress that Africa still faces challenges of limited human, institutional and financial systems capable of attracting climate funding from these developed economies. By using the qualitative multi-case study method supplemented by interviews of key actors and comprehensive textual analysis of relevant literature, this paper dissects the key emissions and air pollutant sources, their impact on the well-being of the African people, and puts forward suggestions as well as a remedial mechanism to these challenges. The findings reveal that whereas climate change mitigation plans appear comprehensive and good on paper for many African countries like Uganda; the lingering political interference, limited research guided planning, lack of population engagement, irrational resource allocation, and limited system and personnel capacity has largely impeded the realization of the set targets. Recommendations have been put forward to address the above climate change impacts that threaten the food security, health, and livelihoods of the people on the continent.

Keywords: Africa, air pollution, climate change, mitigation, emissions, effective planning, institutional strengthening

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2292 Utilization of Sorghum and White Bean Flour for the Production of Gluten Free and Iron Rich Cookies

Authors: Tahra Elobeid, Emmerich Berghofer

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The aim of this study is to find innovative approaches for the production of iron rich foods using natural iron sources. The vehicle used for fortification was sorghum whereas the iron fortificant was white bean. Fortified sorghum cookies were produced from five different mixtures; iron content, iron bioavailability, cookie texture and acceptability were measured. Cookies were prepared from the three fortified flours; 90% sorghum + 10% white bean (S9WB1), 75% sorghum + 25% white bean (S3WB1), 50% sorghum + 50% white bean (S1WB1) and 100% sorghum and 100% white bean. The functional properties gave good results in all the formulations. Statistical analysis of the iron content in the five different cookies showed that there was significant difference at the 95% confidence level (ANOVA). The iron content in all the recipes including the 100% sorghum improved, the increase ranging from 112% in 100% sorghum cookies to 476% in 100% white bean cookies. This shows that the increase in the amount of white bean used for fortification leads to the improvement of the iron content of cookies. The bioavailability of iron ranged from 21.3% in 100% sorghum to 28.6% in 100% white bean cookies. In the 100% sorghum cookies the iron bioavailability increased with reference to raw sorghum due to the addition of eggs. Bioavailability of iron in raw sorghum is 16.2%, therefore the percentage increase ranged from 5.1% to 28.6%. The cookies prepared from 10% white bean (S9WB1) scored the lowest 3.7 in terms of acceptability. They were the least preferred due to their somewhat soft texture. The 30% white bean cookies (S3WB1) gave results comparable to the 50% (S1WB1) and 100% white bean cookies. Cookies prepared with high percentage of white bean (50% and 100% white bean) gave the best results. Therefore cookie formulations from sorghum and white bean are successful in improving the iron status of anaemic individuals.

Keywords: sorghum, white bean, iron content, bioavailable iron, cookies

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2291 The Material Behavior in Curved Glulam Beam of Jabon Timber

Authors: Erma Desmaliana, Saptahari Sugiri

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Limited availability of solid timber in large dimensions becomes a problem. The demands of timbers in Indonesia is more increasing compared to its supply from natural forest. It is associated with the issues of global warming and environmental preservation. The uses of timbers from HTI (Industrial Planting Forest) and HTR (Society Planting Forest), such as Jabon, is an alternative source that required to solve these problems. Having shorter lifespan is the benefit of HTI/HTR timbers, although they are relatively smaller in dimension and lower in strength. Engineering Wood Product (EWP) such as glulam (glue-laminated) timber, is required to overcome their losses. Glulam is fabricated by gluing the wooden planks that having a thickness of 20 to 45 mm with an adhesive material and a certain pressure. Glulam can be made a curved beam, is one of the advantages, thus making it strength is greater than a straight beam. This paper is aimed to know the material behavior of curved glue-laminated beam of Jabon timber. Preliminary methods was to gain physical and mechanical properties, and glue spread strength of Jabon timber, which following the ASTM D-143 standard test method. Dimension of beams were 50 mm wide, 760 mm span, 50 mm thick, and 50 mm rise. Each layer of Jabon has a thickness of 5 mm and is glued with polyurethane. Cold press will be applied to beam laminated specimens for more than 5 hours. The curved glue-laminated beams specimens will be tested about the bending behavior. This experiments aims to obtain the increasing of load carrying capacity and stiffness of curved glulam beam.

Keywords: curved glulam beam, HTR&HTI, load carrying, strength

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2290 Prosecution as Persecution: Exploring the Enduring Legacy of Judicial Harassment of Human Rights Defenders and Political Opponents in Zimbabwe, Cases from 2013-2016

Authors: Bellinda R. Chinowawa

Abstract:

As part of a wider strategy to stifle civil society, Governments routinely resort to judicial harassment through the use of civil and criminal to impugn the integrity of human rights defenders and that of perceived political opponents. This phenomenon is rife in militarised or autocratic regimes where there is no tolerance for dissenting voices. Zimbabwe, ostensibly a presidential republic founded on the values of transparency, equality, freedom, is characterised by brutal suppression of perceived political opponents and those who assert their basic human rights. This is done through a wide range of tactics including unlawful arrests and detention, torture and other cruel, inhuman degrading treatment and enforced disappearances. Professionals including, journalists and doctors are similarly not spared from state attack. For human rights defenders, the most widely used tool of repression is that of judicial harassment where the judicial system is used to persecute them. This can include the levying of criminal charges, civil lawsuits and unnecessary administrative proceedings. Charges preferred against range from petty offences such as criminal nuisance to more serious charges of terrorism and subverting a constitutional government. Additionally, government sponsored individuals and organisations file strategic lawsuits with pecuniary implications order to intimidate and silence critics and engender self-censorship. Some HRDs are convicted and sentenced to prison terms, despite not being criminals in a true sense. While others are acquitted judicial harassment diverts energy and resources away from their human rights work. Through a consideration of statistical data reported by human rights organisations and face to face interviews with a cross section of human rights defenders, the article will map the incidence of judicial harassment in Zimbabwe. The article will consider the multi-level sociological and contextual factors which influence the Government of Zimbabwe to have easy recourse to criminal law and the debilitating effect of these actions on HRDs. These factors include the breakdown of the rule of law resulting in state capture of the judiciary, the proven efficacy of judicial harassment from colonial times to date, and the lack of an adequate redress mechanism at international level. By mapping the use of the judiciary as a tool of repression, from the inception of modern day Zimbabwe to date, it is hoped that HRDs will realise that they are part of a greater community of activists throughout the ages and should emboldened in the realisation that it is an age old tactic used by fallen regimes which should not deter them from calling for accountability.

Keywords: autocratic regime, colonial legacy, judicial harassment, human rights defenders

Procedia PDF Downloads 232
2289 2D Numerical Modeling of Ultrasonic Measurements in Concrete: Wave Propagation in a Multiple-Scattering Medium

Authors: T. Yu, L. Audibert, J. F. Chaix, D. Komatitsch, V. Garnier, J. M. Henault

Abstract:

Linear Ultrasonic Techniques play a major role in Non-Destructive Evaluation (NDE) for civil engineering structures in concrete since they can meet operational requirements. Interpretation of ultrasonic measurements could be improved by a better understanding of ultrasonic wave propagation in a multiple scattering medium. This work aims to develop a 2D numerical model of ultrasonic wave propagation in a heterogeneous medium, like concrete, integrating the multiple scattering phenomena in SPECFEM software. The coherent field of multiple scattering is obtained by averaging numerical wave fields, and it is used to determine the effective phase velocity and attenuation corresponding to an equivalent homogeneous medium. First, this model is applied to one scattering element (a cylinder) in a homogenous medium in a linear-elastic system, and its validation is completed thanks to the comparison with analytical solution. Then, some cases of multiple scattering by a set of randomly located cylinders or polygons are simulated to perform parametric studies on the influence of frequency and scatterer size, concentration, and shape. Also, the effective properties are compared with the predictions of Waterman-Truell model to verify its validity. Finally, the mortar viscoelastic behavior is introduced in the simulation in order to considerer the dispersion and the attenuation due to porosity included in the cement paste. In the future, different steps will be developed: The comparisons with experimental results, the interpretation of NDE measurements, and the optimization of NDE parameters before an auscultation.

Keywords: attenuation, multiple-scattering medium, numerical modeling, phase velocity, ultrasonic measurements

Procedia PDF Downloads 269
2288 Analysis of the Engineering Judgement Influence on the Selection of Geotechnical Parameters Characteristic Values

Authors: K. Ivandic, F. Dodigovic, D. Stuhec, S. Strelec

Abstract:

A characteristic value of certain geotechnical parameter results from an engineering assessment. Its selection has to be based on technical principles and standards of engineering practice. It has been shown that the results of engineering assessment of different authors for the same problem and input data are significantly dispersed. A survey was conducted in which participants had to estimate the force that causes a 10 cm displacement at the top of a axially in-situ compressed pile. Fifty experts from all over the world took part in it. The lowest estimated force value was 42% and the highest was 133% of measured force resulting from a mentioned static pile load test. These extreme values result in significantly different technical solutions to the same engineering task. In case of selecting a characteristic value of a geotechnical parameter the importance of the influence of an engineering assessment can be reduced by using statistical methods. An informative annex of Eurocode 1 prescribes the method of selecting the characteristic values of material properties. This is followed by Eurocode 7 with certain specificities linked to selecting characteristic values of geotechnical parameters. The paper shows the procedure of selecting characteristic values of a geotechnical parameter by using a statistical method with different initial conditions. The aim of the paper is to quantify an engineering assessment in the example of determining a characteristic value of a specific geotechnical parameter. It is assumed that this assessment is a random variable and that its statistical features will be determined. For this purpose, a survey research was conducted among relevant experts from the field of geotechnical engineering. Conclusively, the results of the survey and the application of statistical method were compared.

Keywords: characteristic values, engineering judgement, Eurocode 7, statistical methods

Procedia PDF Downloads 292
2287 The Effect of Adding Microsilica on the Rheological Behavior and Injectability of the Paste in the Injection Molding of Silica-Based Ceramic Cores

Authors: Arghavan Kazemi, Hossein Radipour

Abstract:

Microsilica (silica foam) is a byproduct of ferrosilicon production and silicon metal. Microsilica particles have a spherical shape, an average diameter of 0.15 µm, and a specific surface area of 15-25 m². g-¹. The overall density of this material is 150-700 kg.m-³. Many researchers have investigated the effect of adding microsilica on the flow properties of cement mixtures. This paper investigated the effect of adding microsilica on the flow behavior and injectability of silica-based paste. For this purpose, different percentages of microsilica have been used to prepare the paste. The rheometric test was performed on all the samples with different percentages of microsilica additives using an MCR300 rotary viscometer at a temperature of 70°C. In addition, the ability to inject pastes containing different amounts of microsilica at pressures of 25, 40, 50, and (bar) 60 at constant temperature and flow in a mold with dimensions of 80 × 80 × 0.5 mm³ has been investigated. Then, the effect of microsilica addition on the strength, porosity percentage, and leachability of the sintered core was studied. The results show that the rheological behavior of the paste is pseudoplastic; also, the silane index decreases with the increase in the percentage of microsilica addition, and the viscosity increases. On the other hand, the addition of microsilica has led to the appearance of thixotropic in the paste. By increasing the amount of microsilica, the injectability has significantly improved at low pressures. The strength of the sintered core increases with the increase of microsilica and the amount of remaining porosity and leachability decreases.

Keywords: microsilica, rheological behavior, injectability, injection molding, silica-based ceramic cores, leachability

Procedia PDF Downloads 27
2286 Borate Crosslinked Fracturing Fluids: Laboratory Determination of Rheology

Authors: Lalnuntluanga Hmar, Hardik Vyas

Abstract:

Hydraulic fracturing has become an essential procedure to break apart the rock and release the oil or gas which are trapped tightly in the rock by pumping fracturing fluids at high pressure down into the well. To open the fracture and to transport propping agent along the fracture, proper selection of fracturing fluids is the most crucial components in fracturing operations. Rheology properties of the fluids are usually considered the most important. Among various fracturing fluids, Borate crosslinked fluids have proved to be highly effective. Borate in the form of Boric Acid, borate ion is the most commonly use to crosslink the hydrated polymers and to produce very viscous gels that can stable at high temperature. Guar and HPG (Hydroxypropyl Guar) polymers are the most often used in these fluids. Borate gel rheology is known to be a function of polymer concentration, borate ion concentration, pH, and temperature. The crosslinking using Borate is a function of pH which means it can be formed or reversed simply by altering the pH of the fluid system. The fluid system was prepared by mixing base polymer with water at pH ranging between 8 to 11 and the optimum borate crosslinker efficiency was found to be pH of about 10. The rheology of laboratory prepared Borate crosslinked fracturing fluid was determined using Anton Paar Rheometer and Fann Viscometer. The viscosity was measured at high temperature ranging from 200ᵒF to 250ᵒF and pressures in order to partially stimulate the downhole condition. Rheological measurements reported that the crosslinking increases the viscosity, elasticity and thus fluid capability to transport propping agent.

Keywords: borate, crosslinker, Guar, Hydroxypropyl Guar (HPG), rheology

Procedia PDF Downloads 197
2285 Adhesive Based upon Polyvinyl Alcohol And Chemical Modified Oca (Oxalis tuberosa) Starch

Authors: Samantha Borja, Vladimir Valle, Pamela Molina

Abstract:

The development of adhesives from renewable raw materials attracts the attention of the scientific community, due to it promises the reduction of the dependence with materials derived from oil. This work proposes the use of modified 'oca (Oxalis tuberosa)' starch and polyvinyl alcohol (PVA) in the elaboration of adhesives for lignocellulosic substrates. The investigation focused on the formulation of adhesives with 3 different PVA:starch (modified and native) ratios (of 1,0:0,33; 1,0:1,0; 1,0:1,67). The first step to perform it was the chemical modification of starch through acid hydrolysis and a subsequent urea treatment to get carbamate starch. Then, the adhesive obtained was characterized in terms of instantaneous viscosity, Fourier-transform infrared spectroscopy (FTIR) and shear strength. The results showed that viscosity and mechanical tests exhibit data with the same tendency in relation to the native and modified starch concentration. It was observed that the data started to reduce its values to a certain concentration, where the values began to grow. On the other hand, two relevant bands were found in the FTIR spectrogram. The first in 3300 cm⁻¹ of OH group with the same intensity for all the essays and the other one in 2900 cm⁻¹, belonging to the group of alkanes with a different intensity for each adhesive. On the whole, the ratio PVA:starch (1:1) will not favor crosslinking in the adhesive structure and causes the viscosity reduction, whereas, in the others ones, the viscosity is higher. It was also observed that adhesives made with modified starch had better characteristics, but the adhesives with high concentrations of native starch could equal the properties of the adhesives made with low concentrations of modified starch.

Keywords: polyvinyl alcohol, PVA, chemical modification, starch, FTIR, viscosity, shear strength

Procedia PDF Downloads 150
2284 Investigation of Residual Stress Relief by in-situ Rolling Deposited Bead in Directed Laser Deposition

Authors: Ravi Raj, Louis Chiu, Deepak Marla, Aijun Huang

Abstract:

Hybridization of the directed laser deposition (DLD) process using an in-situ micro-roller to impart a vertical compressive load on the deposited bead at elevated temperatures can relieve tensile residual stresses incurred in the process. To investigate this stress relief mechanism and its relationship with the in-situ rolling parameters, a fully coupled dynamic thermo-mechanical model is presented in this study. A single bead deposition of Ti-6Al-4V alloy with an in-situ roller made of mild steel moving at a constant speed with a fixed nominal bead reduction is simulated using the explicit solver of the finite element software, Abaqus. The thermal model includes laser heating during the deposition process and the heat transfer between the roller and the deposited bead. The laser heating is modeled using a moving heat source with a Gaussian distribution, applied along the pre-formed bead’s surface using the VDFLUX Fortran subroutine. The bead’s cross-section is assumed to be semi-elliptical. The interfacial heat transfer between the roller and the bead is considered in the model. Besides, the roller is cooled internally using axial water flow, considered in the model using convective heat transfer. The mechanical model for the bead and substrate includes the effects of rolling along with the deposition process, and their elastoplastic material behavior is captured using the J2 plasticity theory. The model accounts for strain, strain rate, and temperature effects on the yield stress based on Johnson-Cook’s theory. Various aspects of this material behavior are captured in the FE software using the subroutines -VUMAT for elastoplastic behavior, VUHARD for yield stress, and VUEXPAN for thermal strain. The roller is assumed to be elastic and does not undergo any plastic deformation. Also, contact friction at the roller-bead interface is considered in the model. Based on the thermal results of the bead, the distance between the roller and the deposition nozzle (roller o set) can be determined to ensure rolling occurs around the beta-transus temperature for the Ti-6Al-4V alloy. It is identified that roller offset and the nominal bead height reduction are crucial parameters that influence the residual stresses in the hybrid process. The results obtained from a simulation at roller offset of 20 mm and nominal bead height reduction of 7% reveal that the tensile residual stresses decrease to about 52% due to in-situ rolling throughout the deposited bead. This model can be used to optimize the rolling parameters to minimize the residual stresses in the hybrid DLD process with in-situ micro-rolling.

Keywords: directed laser deposition, finite element analysis, hybrid in-situ rolling, thermo-mechanical model

Procedia PDF Downloads 108
2283 Polyvinyl Alcohol Processed Templated Polyaniline Films: Preparation, Characterization and Assessment of Tensile Strength

Authors: J. Subbalakshmi, G. Dhruvasamhith, S. M. Hussain

Abstract:

Polyaniline (PANI) is one of the most extensively studied material among the conducting polymers due to its simple synthesis by chemical and electrochemical routes. PANIs have advantages of chemical stability and high conductivity making their commercial applications quite attractive. However, to our knowledge, very little work has been reported on the tensile strength properties of templated PANIs processed with polyvinyl alcohol and also, detailed study has not been carried out. We have investigated the effect of small molecule and polymers as templates on PANI. Stable aqueous colloidal suspensions of trisodium citrate (TSC), poly(ethylenedioxythiophene)-polystyrene sulfonate (PEDOT-PSS), and polyethylene glycol (PEG) templated PANIs were prepared through chemical synthesis, processed with polyvinyl alcohol (PVA) and were fabricated into films by solution casting. Absorption and infra-red spectra were studied to gain insight into the possible molecular interactions. Surface morphology was studied through scanning electron microscope and optical microscope. Interestingly, tensile testing studies revealed least strain for pure PVA when compared to the blends of templated PANI. Furthermore, among the blends, TSC templated PANI possessed maximum elasticity. The ultimate tensile strength for PVA processed, PEG-templated PANI was found to be five times more than other blends considered in this study. We establish structure–property correlation with morphology, spectral characterization and tensile testing studies.

Keywords: surface morphology, processed films, polyvinyl alcohol, templated polyanilines, tensile testing

Procedia PDF Downloads 208
2282 Evaluation of Nematicidal Action of Some Botanicals on Plant-Parasitic Nematode

Authors: Lakshmi, Yakshita Awasthi, Deepika, Lovleen Jha, Archna Kumar

Abstract:

From the back of centuries, plant-parasitic nematodes (PPN) have been recognized as a major threat to agriculturalists globally. It causes 21.3% global food loss annually. The utilization of harmful chemical pesticides to minimize the nematode population may cause acute and delayed health hazards and harmful impacts on human health. In recent years, a variety of plants have been evaluated for their nematicidal properties and efficacy in the management of plant-parasitic nematodes. Several Phyto-nematicides are available, but most of them are incapable of sustainable management of PPN, especially Meloidogyne spp. Thus, there is a great need for a new eco-friendly, highly efficient, sustainable control measure for this nematode species. Keeping all these facts and after reviewing the literature, aqueous extract of Cymbopogon citratus, Tagetes erecta, and Azadirachta indica were prepared by adding distilled water (1 g sample mixed with 10ml of water). In vitro studies were conducted to evaluate the efficacious nature of targeted botanicals against PPN Meloidogyne spp. The mortality status of PPN was recorded by counting the live and dead individuals after applying 100μl of selected extract. The impact was observed at different time durations, i.e., 24h and 48h. The result showed that the highest 100% mortality was at 48h in all three extracts. Thus, these extracts, with the addition of a suitable shelf-life enhancer, may be exploited in different nematode control programs as an economical, sustainable measure.

Keywords: Meloidogyne, Cymbopogon citratus, Tagetes erecta, Azadirachta indica, nematicidal

Procedia PDF Downloads 159
2281 High Pressure Delignification Process for Nanocrystalline Cellulose Production from Agro-Waste Biomass

Authors: Sakinul Islam, Nhol Kao, Sati Bhattacharya, Rahul Gupta

Abstract:

Nanocrystalline cellulose (NCC) has been widely used for miscellaneous applications due to its superior properties over other nanomaterials. However, the major problems associated with the production of NCC are long reaction time, low production rate and inefficient process. The mass production of NCC within a short period of time is still a great challenge. The main objective of this study is to produce NCC from rice husk agro waste biomass from a high pressure delignification process (HPDP), followed by bleaching and hydrolysis processes. The HPDP has not been explored for NCC production from rice husk biomass (RHB) until now. In order to produce NCC, powder rice husk (PRH) was placed into a stainless steel reactor at 80 ˚C under 5 bars. Aqueous solution of NaOH (4M) was used for the dissolution of lignin and other amorphous impurities from PRH. After certain experimental times (1h, 3.5h and 6h), bleaching and hydrolysis were carried out on delignified samples. NaOCl (20%) and H2SO4 (4M) solutions were used for bleaching and hydrolysis processes, respectively. The NCC suspension from hydrolysis was sonicated and neutralized by buffer solution for various characterisations. Finally NCC suspension was dried and analyzed by FTIR, XRD, SEM, AFM and TEM. The chemical composition of NCC and PRH was estimated by TAPPI (Technical Association of Pulp and Paper Industry) standard methods to observe the product purity. It was found that, the 6h of the HPDP was more efficient to produce good quality NCC than that at 1h and 3.5h due to low separation of non-cellulosic components from RHB. The analyses indicated the crystallinity of NCC to be 71 %, particle size of 20-50 nm (diameter) and 100-200 nm in length.

Keywords: nanocrystalline cellulose, NCC, high pressure delignification, bleaching, hydrolysis, agro-waste biomass

Procedia PDF Downloads 261
2280 Performance Assessment of a Variable-Flux Permanent-Magnet Memory Motor

Authors: Michel Han, Christophe Besson, Alain Savary, Yvan Becher

Abstract:

The variable flux permanent magnet synchronous motor (VF-PMSM), also called "Memory Motor", is a new generation of motor capable of modifying the magnetization state with short pulses of current during operation or standstill. The impact of such operation is the expansion of the operating range in the torque-speed characteristic and an improvement in energy efficiency at high-speed in comparison to conventional permanent magnet synchronous machines (PMSMs). This paper reviews the operating principle and the unique features of the proposed memory motor. The benefits of this concept are highlighted by comparing the performance of the rotor of the VF-PMSM to that of two PM rotors that are typically found in the industry. The investigation emphasizes the properties of the variable magnetization and presents the comparison of the torque-speed characteristic with the capability of loss reduction in a VF-PMSM by means of experimental results, especially when tests are conducted under identical conditions for each rotor (same stator, same inverter and same experimental setup). The experimental results demonstrated that the VF-PMSM gives an additional degree of freedom to optimize the efficiency over a wide speed range. Thus, with a design easy to manufacture and with the possibility of controlling the magnetization and the demagnetization of the magnets during operations, the VF-PMSM can be interesting for various applications.

Keywords: efficiency, magnetization state, memory motors, performances, permanent-magnet, synchronous machine, variable-flux, variable magnetization, wide speed application

Procedia PDF Downloads 187
2279 Catalytic Thermodynamics of Nanocluster Adsorbates from Informational Statistical Mechanics

Authors: Forrest Kaatz, Adhemar Bultheel

Abstract:

We use an informational statistical mechanics approach to study the catalytic thermodynamics of platinum and palladium cuboctahedral nanoclusters. Nanoclusters and their adatoms are viewed as chemical graphs with a nearest neighbor adjacency matrix. We use the Morse potential to determine bond energies between cluster atoms in a coordination type calculation. We use adsorbate energies calculated from density functional theory (DFT) to study the adatom effects on the thermodynamic quantities, which are derived from a Hamiltonian. Oxygen radical and molecular adsorbates are studied on platinum clusters and hydrogen on palladium clusters. We calculate the entropy, free energy, and total energy as the coverage of adsorbates increases from bridge and hollow sites on the surface. Thermodynamic behavior versus adatom coverage is related to the structural distribution of adatoms on the nanocluster surfaces. The thermodynamic functions are characterized using a simple adsorption model, with linear trends as the coverage of adatoms increases. The data exhibits size effects for the measured thermodynamic properties with cluster diameters between 2 and 5 nm. Entropy and enthalpy calculations of Pt-O2 compare well with previous theoretical data for Pt(111)-O2, and our Pd-H results show similar trends as experimental measurements for Pd-H2 nanoclusters. Our methods are general and may be applied to wide variety of nanocluster adsorbate systems.

Keywords: catalytic thermodynamics, palladium nanocluster absorbates, platinum nanocluster absorbates, statistical mechanics

Procedia PDF Downloads 160
2278 Poverty Versus Interest-Based Loans in East Africa: Can Interest-Free Loans Rescue the Situation?

Authors: Maulana Ayoub Ali

Abstract:

“Both Socialist as well as the capitalist in the economic systems have proven their failure to ensure economic justice that serves to benefit all in the society, both the rich and the poor. In particular, capitalism is currently causing a terrifying scenario by making the rich richer and the poor poorer” . In this paper, the author looks at the level of exploitation which is taking place to small and middle entrepreneurs (SME’s), government and private employees as well as large investors in East African countries who depends on interest-based loans which undermines their lives every day due to heavy monthly returns. Numbers of families have been evicted from their family premises and SME’s properties have been attached in the courts due to failure to return their loans timely. In fact, there are a lot of issues which have taken place on the ground which badly affected number of families socially and most importantly economically due to engagement in interest-based loans offered by commercial banks in East Africa. This paper looks on the alternative ways of eliminating interest-based loans to better lives of devastated Africans who are almost “dying” of heavy debts generated through higher interest loans. Reaching to that particular root the author has visited various literatures in a bid to deeply investigate and find out the best alternative mode of enabling African SME’s, businessmen and employees to benefit from the interest-free loans. The question is whether interest-free loans can be a long term solution towards poverty alleviation in East Africa generally and Tanzania in particular.

Keywords: interest-free loans, SME’s, financial institutions, poverty, east Africa

Procedia PDF Downloads 326