Search results for: bacterial composition

Authors: Usha N. Murthy, H. B. Rekha, Mahaveer Devoor

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The introduction of more stringent pollution regulations, in relation to financial and social pressures for sustainable development, has pressed toward limiting the volumes of industrial and domestic effluents discharged into the environment-as well as to increase the efforts within research and development of new or more efficient wastewater treatment technologies. Considering both discharge volume and effluent composition, wastewater generated by the textile industry is rated as the most polluting among all industrial sectors. The pollution load is mainly due to spent dye baths, which are composed of unreacted dyes, dispersing agents, surfactants, salts and organics. In the present investigation, the textile dye wastewater was characterized by high colour, chemical oxygen demand (COD), total dissolved solids (TDS) and pH. Electrochemical oxidation process for four plate electrodes was carried out at five different current intensities, out of which 0.14A has achieved maximum percentage removal of COD with 75% and 83% of colour. The COD removal rate in kg COD/h/m2 decreases with increase in the current intensity. The energy consumption increases with increase in the current intensity. Hence, textile dye wastewater can be effectively pre-treated by electrochemical oxidation method where the process limits objectionable colour while leaving the COD associated with organics left for natural degradation thus causing a sustainable reduction in pollution load.

Keywords: electrochemical treatment, COD, colour, environmental engineering

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Authors: C. A. C. Castro, D. C. Urashima, E. P. Silva, P. M. L. Silva

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Since 1920, the industry has almost completely changed the rivets production techniques for the manufacture of permanent welding join production of structures and manufacture of other products. The welding arc is the process more widely used in industries. This is accomplished by the heat of an electric arc which melts the base metal while the molten metal droplets are transferred through the arc to the welding pool, protected from the atmosphere by a gas curtain. The GMAW (Gas metal arc welding) process is influenced by variables such as: Current, polarity, welding speed, electrode, extension, position, moving direction; type of joint, welder's ability, among others. It is remarkable that the knowledge and control of these variables are essential for obtaining satisfactory quality welds, knowing that are interconnected so that changes in one of them requiring changes in one or more of the other to produce the desired results. The optimum values are affected by the type of base metal, the electrode composition, the welding position and the quality requirements. Thus, this paper proposes a new methodology, adding the variable vibration through a mechanism developed for GMAW welding, in order to improve the mechanical and metallurgical properties which does not affect the ability of the welder and enables repeatability of the welds made. For confirmation metallographic analysis and mechanical tests were made.

Keywords: vibration, joining, weldability, GMAW

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Authors: Susana Barreto

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This paper explores a pedagogical exercise that employs family photos as catalysts for teaching visual analysis and inspiring academic writing among MA students. The study aimed to achieve two primary objectives: to impart students with the skills of analyzing images or artifacts and to ignite their writing for research purposes. Conducted at Viana Polytechnic in Portugal, the exercise involved two classes on Arts Management and Art Education Master course comprising approximately twenty students from diverse academic backgrounds, including Economics, Design, Fine Arts, and Sociology, among others. The exploratory exercise involved selecting an old family photo, analyzing its content and context, and deconstructing the chosen images in an intuitive and systematic manner. Students were encouraged to engage in photo elicitation, seeking insights from family/friends to gain multigenerational perspectives on the images. The feedback received from this exercise was consistently positive, largely due to the personal connection students felt with the objects of analysis. Family photos, with their emotional significance, fostered deeper engagement and motivation in the learning process. Furthermore, visual analysing family photos stimulated critical thinking as students interpreted the composition, subject matter, and potential meanings embedded in the images. This practice enhanced their ability to comprehend complex visual representations and construct compelling visual narratives, thereby facilitating the writing process. The exercise also facilitated the identification of patterns, similarities, and differences by comparing different family photos, leading to a more comprehensive analysis of visual elements and themes. Throughout the exercise, students found analyzing their own photographs both enjoyable and insightful. They progressed through preliminary analysis, explored content and context, and artfully interwove these components. Additionally, students experimented with various techniques such as converting photos to black and white, altering framing angles, and adjusting sizes to unveil hidden meanings.The methodology employed included observation, documental analysis of written reports, and student interviews. By including students from diverse academic backgrounds, the study enhanced its external validity, enabling a broader range of perspectives and insights during the exercise. Furthermore, encouraging students to seek multigenerational perspectives from family and friends added depth to the analysis, enriching the learning experience and broadening the understanding of the cultural and historical context associated with the family photos Highlighting the emotional significance of these family photos and the personal connection students felt with the objects of analysis fosters a deeper connection to the subject matter. Moreover, the emphasis on stimulating critical thinking through the analysis of composition, subject matter, and potential meanings in family photos suggests a targeted approach to developing analytical skills. This improvement focuses specifically on critical thinking and visual analysis, enhancing the overall quality of the exercise. Additionally, the inclusion of a step where students compare different family photos to identify patterns, similarities, and differences further enhances the depth of the analysis. This comparative approach adds a layer of complexity to the exercise, ultimately leading to a more comprehensive understanding of visual elements and themes. The expected results of this study will culminate in a set of practical recommendations for implementing this exercise in academic settings.

Keywords: visual analysis, academic writing, pedagogical exercise, family photos

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Authors: Charalambos C. Cleanthous, Ryan Sain, Tabitha Black, Stephen Vera, Suzanne Milton

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A concern when administering questionnaires is whether the participant is providing information that is accurate. The results may be invalid because the person is trying to present oneself in an unrealistic positive manner referred to as ‘faking good’, or in an unrealistic negative manner known as ‘faking bad’. The Balanced Inventory of Desirable Responding (BIDR) was used to assess commercial pilots’ responses on the two subscales of the BIDR: impression management (IM) and self-deceptive enhancement (SDE) that result in high or low scores. Thus, the BIDR produces four valid profiles: IM low and SDE low, IM high and SDE low, IM low and SDE high, and IM high and SDE high. The various profiles were used to compare the respondents’ answers to crew resource management (CRM) items developed from the USA Federal Aviation Administration’s (FAA) guidelines for CRM composition and training. Of particular interest were the results on the IM subscale. The comparisons between those scoring high (lying or faking) versus those low on the IM suggest that there were significant differences regarding their views of the various dimensions of CRM. One of the more disconcerting conclusions is that the high IM scores suggest that the pilots were trying to impress rather than honestly answer the questions regarding their CRM training and practice.

Keywords: USA commercial pilots, crew resource management, faking, social desirability

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Authors: A. T. Ramachandra Naik, H. Shivananda Murthy, H. n. Anjanayappa

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The freshwater prawn, Macrobrachium rosenbergii is a more popular crustacean cultured widely in monoculture system in India. It has got high nutritional value in the human diet. Hence, understanding its enzymatic and body composition is important in order to judge its flesh quality. Fish oil specially derived from Indian oil sardine is a good source of highly unsaturated fatty acid and lipid source in fish/prawn diet. A 35% crude protein diet with graded levels of Sardine oil as a source of fat was incorporated at four levels viz, 2.07, 4.07, 6.07 and 8.07% maintaining a total lipid level of feed at 8.11, 10.24, 12.28 and 14.33% respectively. Diet without sardine oil (6.05% total lipid) was served as basal treatment. The giant freshwater prawn, Macrobrachium rosenbergii was used as test animal and the experiment was lost for 112 days. Significantly, higher gain in weight of prawn was recorded in the treatment with 6.07% sardine oil incorporation followed by higher specific growth rate, food conversion rate and protein efficiency ratio. The 8.07% sardine oil diet produced the highest RNA: DNA ratio in the prawn muscle. Digestive enzyme analyses in the digestive tract and mid-gut gland showed the greatest activity in prawns fed the 8.07% diet.

Keywords: digestive enzyme, fish diet, Macrobrachium rosenbergii, sardine oil

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Authors: Mulatu Kassie Birhanu

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Electrochemical reduction of CO₂ is an emerging and current issue for its conversion in to valuable product upon minimization of its atmospheric level for contribution of maintaining within the range of permissible limit. Among plenty of electro-catalysts gold and copper are efficient and effective catalysts, which are synthesized and applicable for this research work. The two metal catalysts were prepared in inert environment with different compositions through co-reduction process from their corresponding precursors and then by adding multi-walled carbon nano-tube as a supporter and enhanced the conductivity. The catalytic performance of CO₂ reduction for each composition was performed and resulted an outstanding catalytic activity with generation of high current density (70 mA/cm² at 0.91V vs. RHE) and relatively small onset potential. The catalytic performance, compositions, morphologies, structure and geometric arrangements were evaluated by electrochemical analysis (LSV, impedance, chronoamperometry & tafel plot), EDS, SEM and XAS respectively. The composite metals showed better selectivity of products and faradaic efficiencies due to the synergetic effects of the combined nano-particles in addition to the impact of grain size in reduction of CO₂. Carbon monoxide, hydrogen, formate and ethanol are the reduction products, which are detected and quantifiable by chromatographic techniques considering their physical state of each product.

Keywords: carbondioxide, faradaic efficiency, electrocatalyst, current density

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Authors: Apoorva Vinod, Archana Mathur, Snehanshu Saha

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Though there exists a plethora of Activation Functions (AFs) used in single and multiple hidden layer Neural Networks (NN), their behavior always raised curiosity, whether used in combination or singly. The popular AFs –Sigmoid, ReLU, and Tanh–have performed prominently well for shallow and deep architectures. Most of the time, AFs are used singly in multi-layered NN, and, to the best of our knowledge, their performance is never studied and analyzed deeply when used in combination. In this manuscript, we experiment with multi-layered NN architecture (both on shallow and deep architectures; Convolutional NN and VGG16) and investigate how well the network responds to using two different AFs (Sigmoid-Tanh, Tanh-ReLU, ReLU-Sigmoid) used alternately against a traditional, single (Sigmoid-Sigmoid, Tanh-Tanh, ReLUReLU) combination. Our results show that using two different AFs, the network achieves better accuracy, substantially lower loss, and faster convergence on 4 computer vision (CV) and 15 Non-CV (NCV) datasets. When using different AFs, not only was the accuracy greater by 6-7%, but we also accomplished convergence twice as fast. We present a case study to investigate the probability of networks suffering vanishing and exploding gradients when using two different AFs. Additionally, we theoretically showed that a composition of two or more AFs satisfies Universal Approximation Theorem (UAT).

Keywords: activation function, universal approximation function, neural networks, convergence

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Authors: Tahra ElObeid, Omnya Ahmed, Reem Al-Sharshani, Doaa Dalloul, Jannat Alnattei

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Background: Camelus dormedarius camels are also called ‘the Arabian camels’ and are present in the desert area of North Africa and the Middle East. Recently, camel’s milk has a great attention globally because of their proteins and peptides that have been reported to be beneficial for the health and in the management of many diseases. Objectives: This study was designed to investigate the antioxidant, antimicrobial activity and to evaluate the total phenolic content of camel’s milk proteins in Qatar. Methods: Fresh two camel’s milk samples from Omani breed and called Muhajer (camel’s milk A and B) were collected on the 1st of the December. Both samples were from the same location Al- Shahaniyah, Doha, Qatar, but from different local private farms and feeding system. Camel’s milk A and B were defatted by centrifugation and their proteins were extracted by acid and thermal precipitation. The antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Total phenolic compound (TPC) was evaluated by Folin-Ciocalteu reagent (FCR). On the other hand, the antimicrobial activity against eight different type of pathogenic bacteria was evaluated by disc diffusion method and the zone of inhibition was measured. Results: The of the total phenolic content of whole milk in both camel’s milk A and B were significantly the highest among the protein extracts. The % of the DPPH radical inhibition of casein protein in both camel’s milk A and B were significantly the highest among the protein extracts. In this study, there were marked changes in the antibacterial activity in the different camel milk protein extracts. All extracts showed bacterial overgrowth. Conclusion: The antioxidant activity of the camel milk protein extracts correlated to their unique phenolic compounds and bioactive protein peptides. The antimicrobial activity was not detected perhaps due to the technique, the quality, or the extraction method. Overall, camel's milk exhibits a high antioxidant activity, which is responsible for many health benefits besides the nutritional values.

Keywords: camels milk, antioxidant content, antimicrobial activity, proteins, Qatar

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Authors: Akwu A. Nneka, Naidoo, Yougasphree

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A significantly high number of microbes exist in higher plants; these microbes include bacteria, fungi, and actinomycetes. There are reports on the benefits of endophytic fungi and their products of metabolism to the host plant and man, consequently, it is expedient to explore the changes that could arise as a result of manipulating their growth media. Grewia lasiocarpa E. Mey. ex Harv. (Malvaceae) is an indigenous Southern African plant, that belongs to a genus with known medicinal properties. Three media were used to culture the endophytic fungi viz., Potato Dextrose Agar (PDA), Malt Extract Agar (MEA), and Bacteriological Agar (BA) were used singly, and supplemented with three dilutions of the leaves and stem bark extracts. The manipulated growth media composition had a significant effect on the diversity of the isolated fungal populations. Several endophytic fungi were isolated; their distribution and diversity revealed a significant relatedness with the manipulated media. The media supplemented with the plant extracts was observed to give a significant increase in the growth rate and yield of the endophytes. To the best of our knowledge, this is the first study describing the endophytic fungi present in the leaves and stem bark of G. lasiocarpa E. Mey. ex Harv.

Keywords: Grewia lasiocarpa, plant-based extracts, endophytic fungi, Malvaceae

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Authors: Satender Saraswat, Dharmendra Prasad Singh, Rajesh Kumar Verma, Swati Sarswat

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Background and Purpose: The predominant cause of candidiasis was Candida albicans which has shifted towards non-Candida albicans Candida (NCAC) (Candida species other than the C. albicans). NCAC, earlier considered non-pathogenic or minimally virulent, are now considered a primary cause of morbidity and mortality in immunocompromised. With the NCAC spp. gaining weightage in the clinical cases, this study was conducted to determine the prevalence of NCAC spp. in different clinical specimens and to assess a few of their virulence factors. Material and Methods: Routine samples for bacterial culture and sensitivity, showing colony characteristics like Candida on Blood Agar and microscopic features resembling Candida spp. were processed further. Candida isolates were tested for chlamydospore formation, biochemical tests including sugar fermentation and sugar assimilation tests, and growth at 42oC, colony colour on HiCrome™ Candida Differential Agar, HiCandida Identification Kit and VITEK-2 Compact. Virulence factors like adherence to buccal epithelial cells (ABEC), biofilm formation, hemolytic activity, and production of coagulase enzyme were also tested. Results: Mean age of the patients was 38.46 with a male-female ratio of 1.36:1. 137 Candida isolates were recovered. 45.3% isolates were isolated from urine, 19.7% from vaginal swabs and 13.9% from oropharyngeal swabs. 55 (40.1%) isolates of C. albicans and 82 (59.9%) of NCAC spp. were identified, with C. tropicalis (23.4%) in NCAC. C. albicans (3; 50%) was the commonest species in cases of candidemia. Haemolysin production (85.5%) and ABEC (78.2%) were the major virulence factors in C. albicans. C. tropicalis (59.4%) and C. dubliniensis (50%) showed maximum ABEC. Biofilm forming capacity was higher in C. tropicalis (78.1%) than C. albicans (67%). Conclusion: This study suggests varied prevalence and virulence based on geographical locations, even within a subcontinent. It clearly demarcates the emergence of NCAC and their predominance in different body fluids. Identification of Candida to species level should become a routine in all the laboratories.

Keywords: ABEC, NCAC, non-Candida albicans Candida, Vitek-2TM compact

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Authors: Yaser Maher Abdelaziz Hawa

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The Basic-ultrabasic rocks of Bou Azzer ophiolite complex in the Anti-atlas , Morrocco enclose some oxide and sulfide minerals as dissiminated traces. The oxide minerals show a wide variation in composition ranging from Cr-free. Titanomagnetite and ilmenite in the chilled margin gabbro of the upper part of the ophiolite sequence to Al-rich chromian spinel and pure magnetite enclosed in the serpentinized peridotite in the lower part of the sequence. Five mineral assemblages have been distinguished depending on the rock type of the ophiolite sequence. 1-Gersodorfite + Chalcopyrite + Al-Mg rich chromian spinel + pure magnetite, hosted by serpentinized peridotite. 2- Pyrite + Chalcopyrite, enclosed in metagabbro and overlying the ultrabasic cumulates. 3- Al-Fe rich Chromian spinel with rims of Al –rich chromian magnetite enclosed in wherlite. 4- Titanomagnetite replaced by sphene enclosed in marginal Gabbro. 5- Pyrrhotite exsolving Pentlandite + ilmenite + Ilmenite + Al- rich Chromian spinel + magnetite enclosed in fresh olivine olivine in the upper part of the ophiolite sequence.

Keywords: opaques, ophiolites, anti-atlas, morrocco

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Authors: Nizar Abu-Jaber

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Late Pleistocene and Holocene carbonate crusts in the south of Jordan were studied using a combination of field documentation, petrography, geochemical and isotopic techniques. These surficial crusts and vein deposits appear to have formed as a result of interaction between near-surface groundwater, surficial soil and sediments and rising carbon dioxide. Rising mantle CO2 dissolves in the water to create carbonic acid, which in turn dissolves the calcite in the soil in the sediments. When the pH rises later due to degassing, the carbonate crusts are left in the places where the water was flowing in veins, channels and interfaces between high and low permeability materials. The crusts have the potential for being important records of natural and human agencies on the landscape of the area. They reflect the isotopic composition of the waters in which they precipitated in, and also contain isotopic information about the aeolian calcium fluxes affecting the area (using strontium isotopes). Moreover, changing stream valley base levels can be identified and measured, which can help quantify the rates of tectonic movement. Finally, human activities such and channel construction and terrace building can be identified and traced temporally and spatially using these deposits.

Keywords: anthropogenic change, carbonate crusts, environmental change, Jordan

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Authors: Sadek Salah

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The determination of the strength characteristics of waste materials is essential when evaluating the stability of waste fills during initial placement and at the time of closure and rehabilitation of the landfill. Significant efforts, mostly experimental, have been deployed to date in attempts to quantify the mechanical properties of municipal wastes various stages of decomposition. Even though the studies and work done so far have helped in setting baseline parameters and characteristics for waste materials, inherent concerns remain as to the scalability of the findings between the laboratory and the field along with questions as to the suitability of the actual test conditions. These concerns are compounded by the complexity of the problem itself with significant variability in composition, placement conditions, and levels of decay of the various constituents of the waste fills. A complimentary, if not necessarily an alternative approach is to rely on field observations of behavior and instability of such materials. This paper describes an effort at obtaining relevant shear strength parameters from back-analyses of failures which have been observed at a major un-engineered waste fill along the Mediterranean shoreline. Results from the limit-equilibrium failure back-analyses are presented and compared to results from laboratory-scale testing on comparable waste materials.

Keywords: solid waste, shear strength, landfills, slope stability

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Authors: M. L. Ibrahim, A. Abdulhamid

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A surface active molecule synthesized by a rhizobacterial strain Bacillus lentus isolated from Cajanus cajan was investigated. The bioemulsifier was extracted, purified and partially characterized using standard methods. Surface properties of the bioemulsifier were determined by studying the emulsification index, solubility test and stability studies. Partial purification of the bioemulsifier was carried out using FT-IR analysis, Silica-gel column chromatography and thin layer chromatography. GC-MS analysis was carried out to detect the composition and mass of the lipids and esters. The isolate showed an emulsifying activity of 57% and surface activity of 36mm. The stability studies revealed that the bioemulsifier had better stability at temperature of 70oC, 8% pH and 8% NaCl concentration. FT-IR indicated the bioemulsifier to contain peptide and aliphatic chain, TLC revealed the compound to be ninhydrin positive and Column chromatography showed the presence of three amino acids namely; glutamine, valine and cysteine. GC-MS indicated the lipid moiety to contain aliphatic chain ranging from C9-C16 and two major peaks of 1,2-benzenedicarboxylic acid diethyl octyl ester. Therefore, surface active agent from Bacillus lentus can be used effectively in a wide range of applications such as in MEOR and in the biosynthesis of plasticizers for industrial uses.

Keywords: Bacillus lentus, bioemulsifiers, phthalic acid ester, Rhizosphere

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Authors: Bashir Abubakar Abdulkadir, Anita Ramli, Lim Jun Wei, Yoshimitsu Uemura

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In this study, the ZnO/MCM-22 catalyst with different ZnO loading were prepared using conventional wet impregnation process and the catalyst activity was tested for biodiesel production from Jatropha oil. The effects of reaction parameters with regards to catalyst activity were investigated. The synthesized catalysts samples were then characterized by X-ray diffraction (XRD) for crystal phase, Brunauer–Emmett–Teller (BET) for surface area, pore volume and pore size, Field Emission Scanning electron microscope attached to energy dispersive x-ray (FESEM/EDX) for morphology and elemental composition and TPD (NH3 and CO2) for basic and acidic properties of the catalyst. The XRD spectra couple with the EDX result shows the presence of ZnO in the catalyst confirming the positive intercalation of the metal oxide into the mesoporous MCM-22. The synthesized catalyst was confirmed to be mesoporous according to BET findings. Also, the catalysts can be considered as a bifunctional catalyst based on TPD outcomes. Transesterification results showed that the synthesized catalyst was highly efficient and effective to be used for biodiesel production from low grade oil such as Jatropha oil and other industrial application where the high fatty acid methyl ester (FAMEs) yield was achieved at moderate reaction conditions. It was also discovered that the catalyst can be used more than five (5) runs with little deactivation confirming the catalyst to be highly active and stable to the heat of reaction.

Keywords: MCM-22, synthesis, transesterification, ZnO

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Authors: Babatunde Stephen Oladeji, Gloria Asuquo Edet

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The proximate, functional, pasting, and sensory properties of semolina from blends of cassava, maize, and rice were investigated. Cassava, maize, and rice were milled and sieved to pass through a 1000 µm sieve, then blended in the following ratios to produce five samples; FS₁ (40:30:30), FS₂ (20:50:30), FS₃ (25:25:50), FS₄ (34:33:33) and FS₅ (60:20:20) for cassava, maize, and rice, respectively. A market sample of wheat semolina labeled as FSc served as the control. The proximate composition, functional properties, pasting profile, and sensory characteristics of the blends were determined using standard analytical methods. The protein content of the samples ranged from 5.66% to 6.15%, with sample FS₂ having the highest value and being significantly different (p ≤ 0.05). The bulk density of the formulated samples ranged from 0.60 and 0.62 g/ml. The control (FSc) had a higher bulk density of 0.71 g/ml. The water absorption capacity of both the formulated and control samples ranged from 0.67% to 2.02%, with FS₃ having the highest value and FSc having the lowest value (0.67%). The peak viscosity of the samples ranged from 60.83-169.42 RVU, and the final viscosity of semolina samples ranged from 131.17 to 235.42 RVU. FS₅ had the highest overall acceptability score (7.46), but there was no significant difference (p ≤ 0.05) from other samples except for FS₂ (6.54) and FS₃ (6.29). This study establishes that high-quality and consumer-acceptable semolina that is comparable to the market sample could be produced from blends of cassava, maize, and rice.

Keywords: semolina, gluten, celiac disease, wheat allergies

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Authors: Nawel Ganaoui, Chadli Souhila, Gahdab Chakal

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This study presents the results of a comparative research aiming to examine the distribution of beetles in four agroecosystems in the Tiaret region, located in northwestern Algeria, during the year 2023. This study was initiated across 04 stations that were randomly distributed within the Ksar Chellala region and selected based on their plant composition. The sampling method used was based on pitfall traps, which were filled two-thirds with a solution of saltwater supplemented with vinegar. In total, 40 species of beetles belonging to 9 families were identified. Among them, tenebrionids were the most abundant group (43%), followed by scarab beetles (30%) The comparison between the four types of agroecosystems - olive culture, sheep farming, cereal cultivation, and Pomegranate cultivation- in this region revealed that cereal cultivation harbored the greatest species diversity (30 species), followed by the sheep farming site (32 species), and then the other sites based on their ecological importance and trophic interactions, these beetle species were mainly categorized as coprophages, phytophages, and predators. The spatiotemporal evolution of beetle activity highlighted peaks of rich-ness and abundance, mainly during the dry period (from April to May), while the cold period (January) showed the low-est levels. The specific diversity of beetles varied significantly from one habitat to another.

Keywords: agroecosystem, beetle, entomology, steppe regoin

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Authors: Chol Min Yu, Sok Chol Ri

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The optimization of formation and growth of metallic nuggets during self-reduction of coal composite briquette (CCB here) is essential to increase the yield of valuable metals. The formation of metallic nuggets was investigated theoretically and experimentally during the reduction of coal composite briquette made from stainless steel dust and coal. The formation of metallic nuggets is influenced by slag viscosity and interfacial tension between the liquid metal and the slag in the reduced product. Surface tensions of liquid metal and slag are rather strong, respectively, due to the high basicity of its slag. Strong surface tensions of them lead to increase of interfacial tension between the liquid metal and the slag to be favorable to the growth of metallic nuggets. The viscosity of slag and interfacial tension between the liquid metal and the slag depends on the temperature and composition of the slag. The formation and the growth of metallic nuggets depend on carbon to oxygen ratio FC/O and temperature.

Keywords: stainless steel dust, coal-composite briquette, temperature, high basicity, interfacial tension

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Authors: Abhijith N. V., Abhijit Pattnayak, Deepak Kumar

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Nowadays, a group of alloys, namely high entropy alloys (HEA), because of their excellent properties. However, the fabrication of HEAs requires multistage techniques, especially mill-ing, sieving, compaction, sintering, inert media, etc. These processes are laborious, costly, time-oriented, and unsuitable for commercial application. This study adopted a single-stage process-based HVOF thermal spray to develop HEA coating on SS304L substrates. The wear behavior of the deposited HEA coating was explored under different milling time durations (5h, 10h, and 15h, respectively). The effect of feedstock preparation, microstructure, surface chemistry, and mechanical and metallurgical properties on wear resistance was also investigated. The microstructure and composition of both coating and feedstock were evaluated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis. Finally, the phase distribution was correlated by X-ray diffraction (XRD ) analysis. The results showed that 15h milled powder coating indicated better tribological than the base substrate and 5h,10h milled powder coating. A chemically stable Body Centered Cubic (BCC) solid solution phase was generated within the 15h milled powder-coated system, which resulted in superior tribological properties.

Keywords: high entropy alloys coating, wear mechanism, HVOF coating, microstructure

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Authors: J. Satya Eswari, Ch. Venkateswarlu

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The formulation of a commercial pharmaceutical product involves several composition factors and response characteristics. When the formulation requires to satisfy multiple response characteristics which are conflicting, an optimal solution requires the need for an efficient multiobjective optimization technique. In this work, a regression is combined with a non-dominated sorting differential evolution (NSDE) involving Naïve & Slow and ε constraint techniques to derive different multiobjective optimization strategies, which are then evaluated by means of a trapidil pharmaceutical formulation. The analysis of the results show the effectiveness of the strategy that combines the regression model and NSDE with the integration of both Naïve & Slow and ε constraint techniques for Pareto optimization of trapidil formulation. With this strategy, the optimal formulation at pH=6.8 is obtained with the decision variables of micro crystalline cellulose, hydroxypropyl methylcellulose and compression pressure. The corresponding response characteristics of rate constant and release order are also noted down. The comparison of these results with the experimental data and with those of other multiple regression model based multiobjective evolutionary optimization strategies signify the better performance for optimal trapidil formulation.

Keywords: pharmaceutical formulation, multiple regression model, response surface method, radial basis function network, differential evolution, multiobjective optimization

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Authors: Abhilasha Mishra, Neha Bhatt

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Super-hydrophobicity is an effect in which a surface roughness and chemical composition are combined to produce unusual water and dust repellent surface. The super-hydrophobic surface is widely used in many applications such as windshields of the automobile, aircraft, lens, solar cells, roofing, boat hull, paints, etc. Four coating solutions were prepared by varying compositions of 1,1,1,3,3,3 hexametyldisilazane (HDMS) and tetraethylorthosilicate (TEOS) sol. These solutions were coated on glass slides by a spin coating method and etched at a high temperature ranging 250 -350 oC. All the coatings were studied for its different properties like water repellent, anti-dust, and transparency and contact angle measurements. Stability of coatings was also studied with respect to temperature, external environment, and pH. It was found that all coatings impart a significant super-hydrophobicity on a glass surface with contact angle ranging from 156o to 162o and have good stability in the external environment. The results of the different coatings were observed and compared with each other. On increasing layers of coatings the super-hydrophobicity and anti-dust properties increases but after 3 coatings the transparency of coating starts decreasing.

Keywords: super-hydrophobic, contact angle, coating, anti-dust

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Authors: Luz del Carmen Rubí Félix Peña, Jose Adan Felix-Ortiz, Ely Sara Lopez-Alvarez, Wenceslao Valenzuela-Quiñonez

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On a global scale, Mexico is the sixth largest producer of farmed white shrimp (Penaeus vannamei). The activity suffered significant economic losses due to acute hepatopancreatic necrosis (AHPND) caused by a strain of Vibrio parahaemolyticus. For control, the first option is the application of antibiotics in food, causing changes in the environment and bacterial communities, which has produced greater virulence and resistance of pathogenic bacteria. An alternative treatment is silver nanoparticles (AgNPs) generated by green synthesis, which have shown an antibacterial capacity by destroying the cell membrane or denaturing the cell. However, the doses at which these are effective are still unknown. The aim is to calculate the minimum inhibitory concentration (MIC) using the Gompertz, Richard, and Logistic model of biosynthesized AgNPs against a strain of V. parahaemolyticus. Through the testing of different formulations of AgNPs synthesized from Euphorbia prostrate (Ep) extracts against V. parahaemolyticus causing AHPND in white shrimp. Aqueous and ethanol extracts were obtained, and the concentration of phenols and flavonoids was quantified. In the antibiograms, AgNPs were formulated in ethanol extracts of Ep (20 and 30%). The inhibition halo at well dilution test were 18±1.7 and 17.67±2.1 mm against V. parahaemolyticus. A broth microdilution was performed with the inhibitory agents (aqueous and ethanolic extracts and AgNPs) and 20 μL of the inoculum of V. parahaemolyticus. The MIC for AgNPs was 6.2-9.3 μg/mL and for ethanol extract of 49-73 mg/mL. The Akaike index (AIC) was used to choose the Gompertz model for ethanol extracts of Ep as the best data descriptor (AIC=204.8, 10%; 45.5, 20%, and 204.8, 30%). The Richards model was at AgNPs ethanol extract with AIC=-9.3 (10%), -17.5 (20 and 30%). The MIC calculated for EP extracts with the modified Gompertz model were 20 mg/mL (10% and 20% extract) and 40 mg/mL at 30%, while Richard was winner for AgNPs-synthesized it was 5 μg/mL (10% and 20%) and 8 μg/mL (30%). The solver tool Excel was used for the calculations of the models and inhibition curves against V.parahaemolyticus.

Keywords: green synthesis, euphorbia prostata, phenols, flavonoids, bactericide

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Authors: Marta Skwarecka, Patrycja Bloch, Rafal Walkusz, Oliwia Urbanowicz, Grzegorz Zielinski, Sabina Zoledowska, Dawid Nidzworski

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Upper respiratory tract infections are one of the most common reasons for visiting a general doctor. Streptococci are the most common bacterial etiological factors in these infections. There are many different types of Streptococci and infections vary in severity from mild throat infections to pneumonia. For example, S. pyogenes mainly contributes to acute pharyngitis, palatine tonsils and scarlet fever, whereas S. Streptococcus pneumoniae is responsible for several invasive diseases like sepsis, meningitis or pneumonia with high mortality and dangerous complications. There are only a few diagnostic tests designed for detection Streptococci from the infected throat of patients. However, they are mostly based on lateral flow techniques, and they are not used as a standard due to their low sensitivity. The diagnostic standard is to culture patients throat swab on semi selective media in order to multiply pure etiological agent of infection and subsequently to perform antibiogram, which takes several days from the patients visit in the clinic. Therefore, the aim of our studies is to develop and implement to the market a Point of Care device for the rapid identification of Streptococcus pyogenes and Streptococcus pneumoniae with simultaneous identification of antibiotic resistance genes. In the course of our research, we successfully selected genes for to-species identification of Streptococci and genes encoding antibiotic resistance proteins. We have developed a reaction to amplify these genes, which allows detecting the presence of S. pyogenes or S. pneumoniae followed by testing their resistance to erythromycin, chloramphenicol and tetracycline. What is more, the detection of β-lactamase-encoding genes that could protect Streptococci against antibiotics from the ampicillin group, which are widely used in the treatment of this type of infection is also developed. The test is carried out directly from the patients' swab, and the results are available after 20 to 30 minutes after sample subjection, which could be performed during the medical visit.

Keywords: antibiotic resistance, Streptococci, respiratory infections, diagnostic test

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Authors: Mehdi Ghatus

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Two simple apparatus based on the hammer and anvil principle have been constructed and used to study the microstructure and micro-hardness characteristics of some AL-base alloys. Foils with thicknesses arranging from 20 µm up to 600 µm have been obtained. The cooling rate was estimated to be in the range 10^4 - 10^5 K/sec. Microstructure study of rapidly quenched Al-30% Si foils indicated that with decreasing the foil thickness the size of primary Si crystallites decreases in the whole investigated range (0.64-0.15 mm). However, the volume fraction of the primary Si crystals in the structure remained constant down to thickness the primary Si volume fraction started to decrease. Rapid quenching of Al- 14-16% Cu showed single phase cell structure. In foils up to 0.55 mm with decreasing the foil thickness the cell size decreases and micro-hardness increases particularly in foils below 0.3 mm in thickness. Isochronal annealing of theses foils show that the highly supersaturated Al-14-16% Cu solid solution decomposes readily at relatively low temperature and short time intervals. The maximum hardness is obtained after annealing at 100 °C for 30 minutes. However with decreasing the Cu content of the foils the precipitation process is largely delayed. Eight hours of annealing at 100 °C was not enough to achieve the maximum hardness in Al-4% Cu thin foils. The achieved hardness value was more than twice of the maximum hardness obtained in articles of similar composition but conventionally aged.

Keywords: aluminum, hardness, alloys, quenched aluminum

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Authors: Mkhokheli Sithole, Brenda N. Muchapondwa

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Food security is becoming a critical issue for people residing mainly in the rural areas where frequent droughts interrupt food production, reduce income, compromise the ability to save and erode livelihoods. This tends to increase the vulnerability of poor households to food and income insecurity, hence, malnutrition. There is an emerging need for DRR strategies to complement the existing rain fed crop production based livelihoods. One of such strategies employed by the community of Nerumedzo in Bikita district is the harvesting of Encosternum delegorguei insect. This article analyses the livelihood impacts of Encosternum delegorguei insect as a DRR strategy. The research used a combination of qualitative and quantitative approaches. The insect samples were tested in the laboratory for their nutritional composition while surveys were done on a sample of 40 community members. Participatory observations and 5 focus group discussions were also done. The results revealed that harvesting the Encosternum delegorguei insects provides a livelihood for the locals by complementing crop production thereby mitigating potential negative effects of frequent droughts. The insects are now a significant source of income to poor households in the community.

Keywords: disaster risk reduction, livelihoods, human, social sciences

Procedia PDF Downloads 184

Authors: F. Zouai, F. Z. Benabid, S. Bouhelal, D. Benachour

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A method for the exfoliation of polyethylene terephtalate (PET) - clay nanocomposites has been reported in this study. Montmorillonite clay based polyethylene terephtalate nanocomposites were prepared by reactive melt-mixing. To achieve this, untreated clay was first functionalized with the crosslinking agent compound based mainly on peroxide/sulphur and TMTD as accelerator or activator for sulphur. Furthermore, the different blends composition of PET/clay were directly mixed in melt state in closed chamber of plastograph at given working conditions for short time and in one step process. To investigate the microstructure modification and thermal, mechanical and rheological properties the DSC, WAXS, microhardness, FTIR and tensile properties were performed. The resulting structure of the modified samples shows that total exfoliation appears at 4% w/w of clay to PET matrices. The crystallinity and tensile modulus were correlated by the H microhardness and the DSC shows no significant effect on the cristallinity degree. The mechanical properties were improved significantly. The viscosity decreases for 4% clay and the activation energy is the minimum. The WAXS measurement shows a partial exfoliation without any intercalation which is the most relevant point. The grafting of organic to inorganic nanolayers was observed by Si—O—C and Si—C bonds by FTIR.

Keywords: PET, montmorillonite, nanocomposites, exfoliation, reactive melt-mixing

Procedia PDF Downloads 246

Authors: Niki K. Burns, James R. Pearson, Paul G. Stevenson, Xavier A. Conlan

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In Australian state Victoria, synthetic cannabinoids have recently been made illegal under an amendment to the drugs, poisons and controlled substances act 1981. Identification of synthetic cannabinoids in popular brands of ‘incense’ and ‘potpourri’ has been a difficult and challenging task due to the sample complexity and changes observed in the chemical composition of the cannabinoids of interest. This study has developed analytical methodology for the targeted extraction and determination of synthetic cannabinoids available pre-ban. A simple solvent extraction and solid phase extraction methodology was developed that selectively extracted the cannabinoid of interest. High performance liquid chromatography coupled with UV‐visible and chemiluminescence detection (acidic potassium permanganate and tris (2,2‐bipyridine) ruthenium(III)) were used to interrogate the synthetic cannabinoid products. Mass spectrometry and nuclear magnetic resonance spectroscopy were used for structural elucidation of the synthetic cannabinoids. The tris(2,2‐bipyridine)ruthenium(III) detection was found to offer better sensitivity than the permanganate based reagents. In twelve different brands of herbal incense, cannabinoids were extracted and identified including UR‐144, XLR 11, AM2201, 5‐F‐AKB48 and A796‐260.

Keywords: electrospray mass spectrometry, high performance liquid chromatography, solid phase extraction, synthetic cannabinoids

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Authors: J. Belovickis, V. Samulionis, J. Banys, M. V. Silibin, A. V. Solnyshkin, A. V. Sysa

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Ferroelectric polymers exhibit good flexibility, processability and low cost of production. Doping of ferroelectric polymers with nanofillers may modify its dielectric, elastic or piezoelectric properties. Carbon nanotubes are one of the ingredients that can improve the mechanical properties of polymer based composites. In this work, we report on both the ultrasonic and the dielectric properties of the copolymer polyvinylidene fluoride/tetrafluoroethylene (P(VDF-TrFE)) of the composition 70/30 mol% with various concentrations of carbon nanotubes (CNT). Experimental study of ultrasonic wave attenuation and velocity in these composites has been performed over wide temperature range (100 K – 410 K) using an ultrasonic automatic pulse-echo tecnique. The temperature dependences of ultrasonic velocity and attenuation showed anomalies attributed to the glass transition and paraelectric-ferroelectric phase transition. Our investigations showed mechanical losses to be dependent on the volume fraction of the CNTs within the composites. The existence of broad hysteresis of the ultrasonic wave attenuation and velocity within the nanocomposites is presented between cooling and heating cycles. By the means of dielectric spectroscopy, it is shown that the dielectric properties may be tuned by varying the volume fraction of the CNT fillers.

Keywords: carbon nanotubes, polymer composites, PVDF-TrFE, ultrasonic spectroscopy

Procedia PDF Downloads 327

Authors: N. Meziou-Chebouti, A. Merabet, Y. Chebouti N. Behidj

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This work is a contribution to the knowledge of physicochemical characteristics of mature carob followed by evaluation of the activity, antimicrobial phenolics leaves and green pods of Ceratonia siliqua L. physicochemical study shows that mature carob it has a considerable content of sugar (50.90%), but poor in proteins (7%), fat (8%) and also has a high mineral content. The results obtained from phenolic extracts of leaves and green pods of Ceratonia siliqua L. show a wealth leaf phenolic extract especially flavonoids (0,545 mg EqQ/g) relative to the extract of green pods (0,226 mgEqQ/g). Polyphenols leaves have a slightly inhibitory effect on the growth of strains: Staphylococcus aureus, Escherichia coli, Klebsiella pneumoiae, Streptococcus sp and Sanmonella enteritidis, a strong inhibitory effect on the growth of Pseudomonas strain aerogenosa. Moreover, polyphenols pod have a slightly inhibitory effect on the growth of Streptococcus sp strains, Pseudomonas and aerogenosa Sanmonella enteritidis, a slightly inhibitory effect on the growth of Klebsiella pneumoniae strains, E. coli and Staphylococcus aureus.

Keywords: antimicrobial activity, bacteria, clove, Ceratonia siliqua, polyphenols

Procedia PDF Downloads 335

Authors: Wafa Baccouch, Adel Ghith, Xavier Legrand, Faten Fayala

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Textile waste recycling has become a necessity considering the augmentation of the amount of waste generated each year and the ecological problems that landfilling and burning can cause. Textile waste can be recycled into many different forms according to its composition and its final utilization. Using this waste as reinforcement to composite panels is a new recycling area that is being studied. Compared to virgin fabrics, recycled ones present the disadvantage of having lower structural characteristics, when they are eco-friendly and with low cost. The objective of this work is transforming textile waste into composite material with good characteristic and low price. In this study, we used sewing as a method to improve the characteristics of the recycled textile waste in order to use it as reinforcement to composite material. Textile non-woven waste was afforded by a local textile recycling industry. Performances tests were evaluated using tensile testing machine and based on the testing direction for both reinforcements and composite panels; machine and transverse direction. Tensile tests were conducted on sewed and non sewed fabrics, and then they were used as reinforcements to composite panels via epoxy resin infusion method. Rule of mixtures is used to predict composite characteristics and then compared to experimental ones.

Keywords: composite material, epoxy resin, non woven waste, recycling, sewing, textile

Procedia PDF Downloads 568