Search results for: Daniel Santana de Freitas

Authors: Sandile Daniel Ngidi

Abstract:

A brickforce is a product consisting of two main parallel wires joined by in-line welded cross wires. Embedded in the normal thickness of the brickwork joint, the wires are manufactured to a flattened profile to simplify location into the mortar joint without steel build-up problems at lap positions corners/junctions or when used in conjunction with wall ties. A brickforce has been in continuous use since 1918. It is placed in the cement between courses of bricks. Brickforce is used in every course of the foundations and every course above lintel height. Otherwise, brickforce is used every fourth course in between the foundations and lintel height or a concrete slab and lintel height. The brickforce strengthens and stabilizes the wall, especially if you are building on unstable ground. It provides brickwork increased resistance to tensional stresses. Brickforce uses high tensile steel wires, which can withstand high forces but with a very little stretch. This helps to keep crack widths to a minimum. Recently a debate has opened about the purpose of using brickforce in single-story buildings. The debate has been compounded by the fact that there is no consensus about the spacing of brickforce in brickwork or masonry. In addition, very little information had been published on the relative merits of using the same size of brickforce for the different atmospheric conditions in South Africa. This paper aims to compare different types of brickforce systems used in different countries. Conclusions are made to identify the point and location of brickforce that optimize the system.

Keywords: brickforce, masonry concrete, reinforcement, strengthening, wall panels

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Authors: Tien Wei Daniel Hwang

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The computer program inventors, particularly in Fintech, are unwilling to apply for patents in Taiwan after 2014. Passing the ‘statutory subject matter eligibility’ test and becoming the system patent are not the only cause to the reduction in the number of application. Taiwanese court needs to resolve whether the defendants had ‘used’ that software patent in patent direct infringement suit. Both 35 U.S.C. § 271(a) and article 58 paragraph 2 of Taiwan Patent Law don’t define the meaning of ‘use’ in the statutes. Centillion Data Sys., LLC v. Qwest Commc’ns Int’l, Inc. reconsidered the meaning of ‘use’ in system patent infringement, and held that ‘a party must put the invention into service, i.e., control the system as a whole and obtain benefit from it.’ In Taiwan, Intellectual Property Office, Ministry of Economic Affairs, has explained that ‘using’ the patent is ‘achieving the technical effect of the patent.’ Nonetheless, this definition is too broad to apply to not only the software patent but also the traditional patent. To supply the friendly environment for Fintech corporations, this article aims to let Taiwanese court realize why and how United States District Court, S.D. Indiana, Indianapolis Division and United States Court of Appeals, Federal Circuit defined the meaning of ‘use’ in 35 U.S.C. § 271(a). However, this definition is so lax and confuses many defendants in United States. Accordingly, this article indicates the elements in Taiwan Patent Law are different with 35 U.S.C. § 271(a), so Taiwanese court can follow the interpretation of ‘use’ in Centillion Data case without the same obstacle.

Keywords: direct infringement, FinTech, software patent, use

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Authors: Daniel Barros, Carlos Mota, Raul Fangueiro, Pedro Rosa, Gonçalo Domingos, Alfredo Passanha, Norberto Almeida

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The main aim of the work was to compare the ballistic performance of developed composites using different types of fiber woven fabrics [0,90] and different layers orientation (Angle-ply). The ballistic laminate composites were developed using E-glass, S-glass and aramid fabrics impregnated with thermosetting epoxy resin and using different layers orientation (0,0)º and (0,15)º. The idea of the study is to compare the ballistic performance of each laminate produced by studying the velocity loss of the fragment fired into the laminate surface. There are present some mechanical properties for laminates produced using the different types of fiber, where tensile, flexural and impact Charpy properties were studied. Overall, the angle-ply laminates produced using orientations of (0,15)º, despite the slight loss of mechanical properties compared to the (0,0)º orientation, presents better ballistic resistance and dissipation of energy, for lower ballistic impact velocities (under 290 m/s-1). After treatment of ballistic impact results, the S-Glass with (0,15)º laminate presents better ballistic perforce compared to the other combinations studied.

Keywords: ballistic impact, angle-ply, ballistic composite, s-glass fiber, aramid fiber, fabric fiber, energy dissipation, mechanical performance

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Authors: Ben Clapperton, Daniel Stahl, Kimberley Goldsmith, Trudie Chalder

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Chronic fatigue syndrome (CFS) is a condition characterised by chronic disabling fatigue and other symptoms that currently can't be explained by any underlying medical condition. Although clinical trials support the effectiveness of cognitive behaviour therapy (CBT), the success rate for individual patients is modest. Patients vary in their response and little is known which factors predict or moderate treatment outcomes. The aim of the project is to develop a prediction model from baseline characteristics of patients, such as demographics, clinical and psychological variables, which may predict likely treatment outcome and provide guidance for clinical decision making and help clinicians to recommend the best treatment. The project is aimed at identifying subgroups of patients with similar baseline characteristics that are predictive of treatment effects using modern cluster analyses and data mining machine learning algorithms. The characteristics of these groups will then be used to inform the types of individuals who benefit from a specific treatment. In addition, results will provide a better understanding of for whom the treatment works. The suitability of different clustering methods to identify subgroups and their response to different treatments of CFS patients is compared.

Keywords: chronic fatigue syndrome, latent class analysis, prediction modelling, self-organizing maps

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Authors: Daniel Phifer, Anna Prokhodtseva

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DualBeam (FIB-SEM) has long been the technology of choice to sub-sample and characterize materials at site-specific locations which are difficult or impossible to extract by conventional embedding/polishing methods. Whereas Ga based FIB provides excellent resolution and enables precise material removal, the current is usually limited and only allows the extraction of small material biopsies typically ranging from 5-70um wide. Xe Plasma FIB, by contrast, has around 38x more current and can remove more material at the same time to extract significant sized chunks (100-1000um) of materials for further analysis. This increased volume has enabled time-prohibitive investigations like large grain 3D serial sectioning and EBSD and micro-machining for micro-mechanical testing. Investigation of the pore spaces with 3D modeling can determine the relative characteristics of the materials to help design or select properties for best function. Pore spaces can be described with a tortuosity number which is calculated by modules in the 3D analysis software. Xe Plasma FIB technology provides a workflow with sufficient volume to characterize porosity when both large-volume 3D materials characterization and nanometer resolution is required to understand the system.

Keywords: dual-beam, FIB-SEM, porosity, SOFC, solid oxide fuel cell

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Authors: Daniel Nieto, Ramiro Couceiro

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Microfluidic chips have demonstrated their significant application potentials in microbiological processing and chemical reactions, with the goal of developing monolithic and compact chip-sized multifunctional systems. Heat generation and thermal control are critical in some of the biochemical processes. The paper presents a laser direct-write technique for rapid prototyping and manufacturing of microheater chips and its applicability for perfusion cell culture outside a cell incubator. The aim of the microheater is to take the role of conventional incubators for cell culture for facilitating microscopic observation or other online monitoring activities during cell culture and provides portability of cell culture operation. Microheaters (5 mm × 5 mm) have been successfully fabricated on soda-lime glass substrates covered with aluminum layer of thickness 120 nm. Experimental results show that the microheaters exhibit good performance in temperature rise and decay characteristics, with localized heating at targeted spatial domains. These microheaters were suitable for a maximum long-term operation temperature of 120ºC and validated for long-time operation at 37ºC. for 24 hours. Results demonstrated that the physiology of the cultured SW480 adenocarcinoma of the colon cell line on the developed microheater chip was consistent with that of an incubator.

Keywords: laser microfabrication, microheater, bioengineering, cell culture

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Authors: Isabella Lima Leite de Freitas

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The importance of astronomy for humanity is unquestionable. Despite being a robust science, capable of bringing new discoveries every day and quickly increasing the ability of researchers to understand the universe more deeply, scientific research in this area can also help in various applications outside the domain of astronomy. The objective of this study was to review and conduct a descriptive analysis of published studies that presented the importance of astronomy in the area of education. A narrative review of the literature has been performed, considering the articles published in the last five years. As astronomy involves the study of physics, chemistry, biology, mathematics and technology, one of the studies evaluated presented astronomy as the gateway to science, demonstrating the presence of astronomy in 52 school curricula in 37 countries, with celestial movement the dominant content area. Another intervention study, evaluating individuals aged 4-5 years, demonstrated that the attribution of personal characteristics to cosmic bodies, in addition to the use of comprehensive astronomy concepts, favored the learning of science in preschool-age children, considering the use of practical activities of accompaniment and free drawing. Aiming to measure scientific literacy, another study developed in Turkey, motivated the authorities of this country to change the teaching materials and curriculum of secondary schools after the term “astronomy” appeared as one of the most attractive subjects for young people aged 15 to 24. There are also reports in the literature of the use of pedagogical tools, such as the representation of the Solar System on a human scale, where students can walk along the orbits of the planets while studying the laws of dynamics. The use of this tool favored the teaching of the relationship between distance, duration and speed over the period of the planets, in addition to improving the motivation and well-being of students aged 14-16. An important impact of astronomy on education was demonstrated in the study that evaluated the participation of high school students in the Astronomical Olympiads and the International Astronomy Olympiad. The study concluded that these Olympics have considerable influence on students who pursue a career in teaching or research later on, many of whom are in the area of astronomy itself. In addition, the literature indicates that the teaching of astronomy in the digital age has facilitated the availability of data for researchers, but also for the general population. This fact can increase even more the curiosity that the astronomy area has always instilled in people and promote the dissemination of knowledge on an expanded scale. Currently, astronomy has been considered an important ally in strengthening the school curricula of children, adolescents and young adults. This has been used as teaching tools, in addition to being extremely useful for scientific literacy, being increasingly used in the area of education.

Keywords: astronomy, education area, teaching, review

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Authors: Joy Marie Mora, Mark Daniel De Luna, Tsair-Wang Chung

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Transesterification reaction of soybean oil with methanol was carried out to produce fatty acid methyl esters (FAME) using calcined alkali metal (Na and Li) supported by pumice silica as the solid base catalyst. Pumice silica catalyst was activated by loading alkali metal ions to its surface via an ion-exchange method. Response surface methodology (RSM) in combination with Box-Behnken design (BBD) was used to optimize the operating parameters in biodiesel production, namely: reaction temperature, methanol to oil molar ratio, reaction time, and catalyst concentration. Using the optimized sets of parameters, FAME yields using sodium and lithium silicate catalysts were 98.80% and 98.77%, respectively. A pseudo-first order kinetic equation was applied to evaluate the kinetic parameters of the reaction. The prepared catalysts were characterized by several techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) sorptometer, and scanning electron microscopy (SEM). In addition, the reusability of the catalysts was successfully tested in two subsequent cycles.

Keywords: alkali metal, biodiesel, Box-Behnken design, heterogeneous catalyst, kinetics, optimization, pumice, transesterification

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Authors: Jack S. Pullman, Daniel Wen, Avinash Sharma, Bert Van Der Werf, Richard Martin

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Background: New Zealand (NZ) melanoma incidence rates are amongst the highest in the world. Previous studies investigating the incidence of melanoma in NZ were performed for the periods 1995 – 1999 and 2000 – 2004 and suggested increasing melanoma incidence rates. Aim: The aim of the study is to provide an up-to-date review of trends in cutaneous melanoma in NZ from the New Zealand Cancer Registry (NZCR) 2010 – 2020. Methods: De-identified data were obtained from the NZCR, and relevant demographic and histopathologic information was extracted. Statistical analyses were conducted to calculate age-standardized incidence rates for invasive melanoma (IM) and melanoma in situ (MIS). Secondary results included Breslow thickness and melanoma subtype analysis. Results: There was a decline in the IM age-standardized incidence rate from 30.4 to 23.9 per 100,000 person-years between 2010 to 2020, alongside an increase in MIS incidence rate from 37.1 to 50.3 per 100,000 person-years. Men had a statistically significant higher IM incidence rate (p <0.001) and Breslow thickness (p <0.001) compared with women. Increased age was associated with a higher incidence of IM, presentation with melanoma of greater Breslow thickness and more advanced T stage. Conclusion: The incidence of IM in NZ has decreased in the last decade and was associated with an increase in MIS incidence over the same period. This can be explained due to earlier detection, dermoscopy, the maturity of prevention campaigns and/or a change in skin protection behavior.

Keywords: melanoma, incidence, epidemiology, New Zealand

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Authors: Daniela Magalhaes, Jorge Pedro, Pedro Souteiro, Joao S. Neves, Sofia Castro-Oliveira, Vanessa Guerreiro, Rita Bettencourt- Silva, Maria M. Costa, Ana Varela, Joana Queiros, Paula Freitas, Davide Carvalho

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Introduction: Obesity is an independent risk factor for renal dysfunction. Our aims were: (1) evaluate the impact of bariatric surgery (BS) on renal function; (2) clarify the factors determining the postoperative evolution of the glomerular filtration rate (GFR); (3) access the occurrence of oxalate-mediated renal complications. Methods: We investigated a cohort of 1448 obese patients who underwent bariatric surgery. Those with basal GFR (GFR0) < 30mL/min or without information about the GFR 2-year post-surgery (GFR2) were excluded. Results: We included 725 patients, of whom 647 (89.2%) women, with 41 (IQR 34-51) years, a median weight of 112.4 (IQR 103.0-125.0) kg and a median BMI of 43.4 (IQR 40.6-46.9) kg/m2. Of these, 459 (63.3%) performed gastric bypass (RYGB), 144 (19.9%) placed an adjustable gastric band (AGB) and 122 (16.8%) underwent vertical gastrectomy (VG). At 2-year post-surgery, excess weight loss (EWL) was 60.1 (IQR 43.7-72.4) %. There was a significant improve of metabolic and inflammatory status, as well as a significant decrease in the proportion of patients with diabetes, arterial hypertension and dyslipidemia (p < 0.0001). At baseline, 38 (5.2%) of subjects had hyperfiltration with a GFR0 ≥ 125mL/min/1.73m2, 492 (67.9%) had a GFR0 90-124 mL/min/1.73m2, 178 (24.6%) had a GFR0 60-89 mL/min/1.73m2, and 17 (2.3%) had a GFR0 < 60 mL/min/1.73m2. GFR decreased in 63.2% of patients with hyperfiltration (ΔGFR=-2.5±7.6), and increased in 96.6% (ΔGFR=22.2±12.0) and 82.4% (ΔGFR=24.3±30.0) of the subjects with GFR0 60-89 and < 60 mL/min/1.73m2, respectively ( p < 0.0001). This trend was maintained when adjustment was made for the type of surgery performed. Of 321 patients, 10 (3.3%) had a urinary albumin excretion (UAE) > 300 mg/dL (A3), 44 (14.6%) had a UAE 30-300 mg/dL (A2) and 247 (82.1%) has a UAE < 30 mg/dL (A1). Albuminuria decreased after surgery and at 2-year follow-up only 1 (0.3%) patient had A3, 17 (5.6%) had A2 and 283 (94%) had A1 (p < 0,0001). In multivariate analysis, the variables independently associated with ΔGFR were BMI (positively) and fasting plasma glucose (negatively). During the 2-year follow-up, only 57 of the 725 patients had transient urinary excretion of calcium oxalate crystals. None has records of oxalate-mediated renal complications at our center. Conclusions: The evolution of GFR after BS seems to depend on the initial renal function, as it decreases in subjects with hyperfiltration, but tends to increase in those with renal dysfunction. Our results suggest that BS is associated with improvement of renal outcomes, without significant increase of renal complications. So, apart the clear benefits in metabolic and inflammatory status, maybe obese adults with nondialysis-dependent CKD should be referred for bariatric surgery evaluation.

Keywords: albuminuria, bariatric surgery, glomerular filtration rate, renal function

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Authors: Iddrisu Ibrahim, Joseph Atia Ayariga, Junhuan Xu, Daniel A. Abugri, Robertson K. Boakai, Olufemi S. Ajayi

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The recalcitrance of pathogenic bacteria indicates that millions of people who are at risk of infection arising from chronic diseases, surgery, organ transplant, diabetes, and several other debilitating diseases present an aura of potentially untreatable illness due to resistance development. Antimicrobial resistance has successfully become a global health menace, and resistances are often acquired by bacteria through health-care-related incidence (HRI) orchestrated by multi-drug resistant (MDR) and extended drug-resistant pathogens (EDRP). To understand the mechanisms S. Typhimurium uses to resist CDB, we study the abundance of LPS modification, Ergosterols, Mysristic palmitic resistance, Oleic acid resistance of susceptible and resistant S. Typhimurium. Using qPCR, we also analyzed the expression of selected genes known for enabling resistance in S. Typhimurium. We found high abundance of LPS, Ergosterols, Mysristic palmitic resistance, Oleic acid resistance of and high expression of resistant genes in S. Typhimurium compared to the susceptible strain. LPS modification, Ergosterols, Mysristic palmitic resistance, Oleic acid and genes such as Fims, integrons, blaTEM are important indicators of resistance development of S. typhimurium.

Keywords: antimicrobials, resistance, Cannabidiol, Salmonella, blaTEM, fimA, Lipopolysaccharide, Ergosterols

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Authors: Nahwera L., Constance A. N. Nsibamb, Mukana R., Daniel T. Goon

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Regular physical activity is a cornerstone of maintaining good health. Studies have shown that physical inactivity leads to overweight and obesity, a risk factor for non-communicable diseases and a public health challenge. Health clubs provide therapeutic exercises to clients desiring to reduce their weight; however, the exercise routines offered in these health clubs are insufficient to reduce their body weight. A convenient sample of 100 clients. Exercise routines were determined using a questionnaire. Height, weight, waist, and hip circumferences were measured. Body mass index (BMI), waist circumference, and waist-to-hip ratio (WHR) assessed body weight status. About 75% of clients exercised three or more times per week; 96% participated in modern intensity exercises for 30 minutes, aerobic dance (88%), treadmill (56%), cycling (51%), rope skipping (45%), and 14% in strengthening activities. The BMI of male and female clients was 64.2% and 83.0%, respectively. There was no significant correlation (p≤0.05) between BMI and WHR (p=0.336), although there was a significant correlation between BMI and waist circumference (p=0.000). There was no significant relationship between BMI and WHR for males (p= .336) and between BMI and WHR for females (p=.806). Although most clients visiting health clubs meet the recommended frequency, intensity, and duration of exercise, they are overweight and obese. Appropriate exercise and nutritional programs should be incorporated into health clubs offering therapeutic and rehabilitative exercises to clients.

Keywords: Body weight status, exercise routines, health clubs, exercises

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Authors: D. Lopes, I. I. R. Baptista, R. F. Vieira, J. Vaz, H. Varela, O. M. Freitas, V. F. Domingues, R. Jorge, C. Delerue-Matos, S. A. Figueiredo

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Deodorization is nowadays a need in wastewater treatment plants. Nitrogen and sulphur compounds, volatile fatty acids, aldehydes and ketones are responsible for the unpleasant odours, being ammonia, hydrogen sulphide and mercaptans the most common pollutants. Although chemical treatments of the air extracted are efficient, these are more expensive than biological treatments, namely due the use of chemical reagents (commonly sulphuric acid, sodium hypochlorite and sodium hydroxide). Biofiltration offers the advantage of avoiding the use of reagents (only in some cases, nutrients are added in order to increase the treatment efficiency) and can be considered a sustainable process when the packing medium used is of natural origin. In this work the application of some natural materials locally available was studied both at laboratory and pilot scale, in a real wastewater treatment plant. The materials selected for this study were indigenous Portuguese forest materials derived from eucalyptus and pinewood, such as woodchips and bark, and coconut fiber was also used for comparison purposes. Their physico-chemical characterization was performed: density, moisture, pH, buffer and water retention capacity. Laboratory studies involved batch adsorption studies for ammonia and hydrogen sulphide removal and evaluation of microbiological activity. Four pilot-scale biofilters (1 cubic meter volume) were installed at a local wastewater treatment plant treating odours from the effluent receiving chamber. Each biofilter contained a different packing material consisting of mixtures of eucalyptus bark, pine woodchips and coconut fiber, with added buffering agents and nutrients. The odour treatment efficiency was monitored over time, as well as other operating parameters. The operation at pilot scale suggested that between the processes involved in biofiltration - adsorption, absorption and biodegradation - the first dominates at the beginning, while the biofilm is developing. When the biofilm is completely established, and the adsorption capacity of the material is reached, biodegradation becomes the most relevant odour removal mechanism. High odour and hydrogen sulphide removal efficiencies were achieved throughout the testing period (over 6 months), confirming the suitability of the materials selected, and mixtures thereof prepared, for biofiltration applications.

Keywords: ammonia hydrogen sulphide and removal, biofiltration, natural materials, odour control in wastewater treatment plants

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Authors: Daniel P. Kisangau, Ken M. Hosea, Herbert V. M. Lyaruu, Cosam C. Josep, Zakaria H. Mbwambo, Pax J. Masimba

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Crude extracts of Dracaena steudneri bark (DSB), Sapium ellipticum bark (SEB) and Capparis erythrocarpos root (CER) were investigated for their antifungal activity in immunocompromised mice infected with Candida albicans in an in vivo mice infection model. The results revealed a substantial dose dependency in all treatments given, with mice survival to the end of the experiment correlating well to the dose levels. At a dose of 400 mg/kg, C. erythrocarpos was the most effective with mice survival of 60% and organ burden clearance ranging from 64.0%-99.9% (P<0.0001) in all treatments. At the same dose, the least effective plant was S. ellipticum which had a mice survival of 20% and organ burden clearance ranging from 78.0%-96.6 (P>0.05). Mice survival for D. steudneri was 30% with organ burden clearance ranging from 89.0%-99.9% (P<0.05). All mice receiving no active treatment died before ten days post infection. In all treatment groups, there was a steady decline in mean weights of mice immediately after immunosuppression followed by gradual recovery in some cases which appeared to be dose dependent a few days post infection. Thus, extracts of D. steudneri and C. erythrocarpos portrayed the most significant potential as sources of antifungal drugs.

Keywords: antifungal activity, medicinal plants, candida albicans, East Africa

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Authors: Daniel Y. Abebe, Jaehyouk Choi

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The idea of adding metallic energy dissipaters to a structure to absorb a large part of the seismic energy began four decades ago. There are several types of metal-based devices conceived as dampers for the seismic energy absorber whereby damages to the major structural components could be minimized for both new and existing structures. This paper aimed to develop and evaluate structural performance of both stiffened and non stiffened circular shear panel damper for passive seismic energy protection by inelastic deformation. Structural evaluation was done using commercially available nonlinear FE simulation program. Diameter-to-thickness ratio is employed as main parameter to investigate the hysteresis performance of stiffened and unstiffened circular shear panel. Depending on these parameters three different buckling mode and hysteretic behavior was found: yielding prior to buckling without strength degradation, yielding prior to buckling with strength degradation and yielding with buckling and strength degradation which forms pinching at initial displacement. Hence, the hysteresis behavior is identified, specimens which deform without strength degradation so it will be used as passive energy dissipating device in civil engineering structures.

Keywords: circular shear panel damper, FE analysis, hysteretic behavior, large deformation

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Authors: Steven Mavhungu, Didier Nyembwe, Daniel Sekotlong

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The steering knuckle is an integral component of the suspension and stability control system of modern vehicles. Good mechanical properties with an emphasis on the fatigue properties are essential for this component as it is subjected to cyclical load of significant magnitude during service. These properties are a function of the microstructure achieved in the component during the various manufacturing processes including forging and casting. The strut mount of the knuckle is required to meet specified microstructure and mechanical properties. However, in line with the recent trend of stringent quality requirements of cast components, Original Equipment Manufacturers (OEMs) have had to extend the specifications to other sections of the knuckle. This paper evaluates the effect of cored wire inoculation on the microstructure and mechanical properties of the steering arm of a typical spheroidal cast iron component. The investigation shows that the use of a cored wire having higher rare earth content formulation could possibly lead to a homogeneous matrix containing consistent graphite nodule morphology. However, this was found not to be the condition for better mechanical properties along the knuckle arm in line with required specifications. The findings in this paper contribute to a better understanding of steering knuckle properties to allow its production for safer automobile applications.

Keywords: inoculation, magnesium cored wire, spheroidal graphie, steering knuckle

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Authors: Daniel Isaac Sanchez Chavez, Salvador Rodríguez Zaragoza, Patricia Velez Aguilar

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In arid and semi-arid regions, plants are essential in the functional activity and productivity, modifying the microclimatic conditions of their environment, which allows many organisms to grow under them. Within these organisms, oribatid mites play a key role in reintegrating nutrients into the soil through the consumption of soil fungi. However, oribatid mites feed on a vast array of fungal species, which is likely to have strong impacts on their population dynamics and their environment. So, in this study, the aim was to determine the gut content of the abundant oribatid mites Zygoribatula sp and Scheloribates sp, under the canopy of the bush P. laevigata in a semi-arid zone through DNA-based analysis. The results showed the presence in the gut of both mites of different fungal taxa. Fungi, such as Aspergillus sp and Mortierella sp, probably served as a food despite the production of deterrent compounds or structures from both fungal species. Saccharomyces sp might serve as well as a food source; however, it might be part of their microbial endosymbionts. On the other hand, the presence of Beauveria sp indicates a probable pathogenicity interaction, instead of fungal consumption, since this fungus is known to be entomopathogenic. Finally, the results might indicate a feeding preference to certain soil fungi according to diverse features from both taxa.

Keywords: microenvironment, endosymbionts, Oribatida, fungi

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Authors: Florencio D. De Los Reyes, Magdaleno R. Vasquez Jr., Mark Daniel G. De Luna, Peerasak Paoprasert

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The effect of adding silica nanoparticles (SiNPs) obtained from rice husk, and phosphorus and nitrogen based compounds namely 9,10-dihydro-9-oxa-10-phosphaphenantrene-10-oxide (DOPO) and melamine, respectively, on the flammability of polystyrene (PS) was studied using response surface methodology (RSM). The flammability of PS was reduced as the limiting oxygen index (LOI) values increased when the flame retardant additives were added. DOPO exhibited the best retarding property increasing the LOI value of PS by 42.4%. A quadratic model for LOI was obtained from the RSM results, with percent loading of SiNPs, DOPO, and melamine, as independent variables. The observed increase in the LOI value as the percent loading of the flame retardant additives is increased, was attributed both to the main effects and synergistic effects of the parameters, as the LOI response of SiNPs is greatly enhanced by the addition of DOPO and melamine, as shown by the response surface plots. This indicates the potential of producing a cheaper, effective, and non-toxic multi-flame retardant system for the polymeric system via different flame retarding mechanisms.

Keywords: flame retardancy, polystyrene, response surface methodology, rice husk, silica nanoparticle

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Authors: Sofiane Bendoukha, Daniel Moldt, Hayat Bendoukha

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Workflow concepts are essential for the development of remote sensing applications. They can help users to manage and process satellite data and execute scientific experiments on distributed resources. The objective of this paper is to introduce an approach for the specification and the execution of complex scientific workflows in Cloud-like environments. The approach strives to support scientists during the modeling, the deployment and the monitoring of their workflows. This work takes advantage from Petri nets and more pointedly the so-called reference nets formalism, which provides a robust modeling/implementation technique. RENEWGRASS is a tool that we implemented and integrated into the Petri nets editor and simulator RENEW. It provides an easy way to support not experienced scientists during the specification of their workflows. It allows both modeling and enactment of image processing workflows from the remote sensing domain. Our case study is related to the implementation of vegetation indecies. We have implemented the Normalized Differences Vegetation Index (NDVI) workflow. Additionally, we explore the integration possibilities of the Cloud technology as a supplementary layer for the deployment of the current implementation. For this purpose, we discuss migration patterns of data and applications and propose an architecture.

Keywords: cloud computing, scientific workflows, petri nets, RENEWGRASS

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Authors: Mejbri Sami, Zhani Khalifa, Zarzoum Kamel, Ben Bacha Habib, Koschikowski Joachim, Pfeifle Daniel

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Many places worldwide, especially arid and semi-arid remote regions, are suffering from the lack of drinkable water and the situation will be aggravated in the near future. Furthermore, remote areas are characterised by lack of conventional energy sources, skilled personnel and maintenance facilities. Therefore, the development of small to medium size, stand-alone and robust solar desalination systems is needed to provide independent fresh water supply in remote areas. This paper is focused on experimental studies on compact membrane distillation (MD) solar desalination prototype located at the Mechanical Engineering Department site, Kairouan University, Kairouan, Tunisia. The pilot system is designed and manufactured as a part of a research and development project funded by the MESRS/BMBF. The pilot system is totally autonomous. The electrical energy required to operate the unit is generated through a field of 4 m² of photovoltaic panels, and the heating of feed water is provided by a field of 6 m² of solar collectors. The Kairouan plant performance of the first few months of operation is presented. The highest freshwater production of 150 L/d is obtained on a sunny day in July of 633 W/m²d.

Keywords: experimental, membrane distillation, solar desalination, Permeat gap

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Authors: Daniel N. L. Alves, Marcelo C. Rodrigues, Jose G. de Almeida

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The search for structural efficiency in mechanical systems has been strongly exerted with aim of economic optimization and structural safety. As soon, to understand the response of materials when submitted to adverse conditions is essential to design a safety project. This work investigates the presence of cracks in dissimilar welded joints (DWJ). Its fracture toughness responses depend upon the heterogeneity present in these joints. Thus, this work aim analyzing the behavior of the crack tip zone located in a buttery dissimilar welded joint (ASTM A-36, Inconel, and AISI 8630 M) used in the union of pipes present in the offshore oil production lines. The crack was placed 1 mm from fusion line (FL) Inconel-AISI 8630 M toward the AISI 8630 M. Finite Element Method (FEM) was used to analyze stress and strain fields generated during the loading imposed on the specimen. It was possible observing critical stress area by the numerical tool as well as a preferential plastic flow was also observed in the sample of dissimilar welded joint, which can be considered a harbinger of the crack growth path. The results obtained through numerical analysis showed a convergent behavior in relation to the plastic flow, qualitatively and quantitatively, in agreement with previous performed.

Keywords: crack, dissimilar welded joint, numerical analysis, strain field, the stress field

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Authors: Nicolae Daniel Stoica, Ion Mierlus Mazilu

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This work is one of numerical research and aims to address the issue of the design of new buildings in a 3D location of existing buildings. In today's continuous development and congestion of urban centers is a big question about the influence of the new buildings on an already existent vicinity site. Thus, in this study, we tried to focus on how existent buildings may be affected by any newly constructed buildings and in how far this influence is really decreased. The problem of modeling the influence of interaction between buildings is not simple in any area in the world, and neither in Romania. Unfortunately, most often the designers not done calculations that can determine how close to reality these 3D influences nor the simplified method and the more superior methods. In the most literature making a "shield" (the pilots or molded walls) is absolutely sufficient to stop the influence between the buildings, and so often the soil under the structure is ignored in the calculation models. The main causes for which the soil is neglected in the analysis are related to the complexity modeling of interaction between soil and structure. In this paper, based on a new simple but efficient methodology we tried to determine for a lot of study cases the influence, in terms of assessing the interaction land structure on the behavior of structures that influence a new building on an existing one. The study covers additional subsidence that may occur during the execution of new works and after its completion. It also highlighted the efforts diagrams and deflections in the soil for both the original case and the final stage. This is necessary to see to what extent the expected impact of the new building on existing areas.

Keywords: soil, structure, interaction, piles, earthquakes

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Authors: Daniel Vaati Nzioka, John Oredo, Dorothy Muthoni Njiraine

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The service delivery in academic libraries has been regressing due to the failure of Digital Librarians (DLns) to perform optimally. This study aimed at developing a proposed framework for digital librarianship in academic libraries with special emphasis to three selected public academic institutional libraries. The study’s specific objectives were to determine the roles played by the current DLns’ in academic libraries, establish job description of DLns’ in various academic libraries, ascertain DLns best practices, and to implement a viable digital librarianship conceptual framework. The study used a survey research with open-ended questionnaire designed as per the objectives of the study. A purposively selected sample of 30 Library and Information Science (LIS) professionals from the three selected academic libraries in charge of Digital Information Services (DIS) and managing electronic resources were selected and interviewed. A piloted self-administered questionnaire was used to gather information from these respondents. A total of thirty (30) questionnaires to the LIS professionals-ten from each of the three selected academic libraries were administered. The study developed a proposed conceptual framework for DLns’ that details the pertinent issues currently facing academic libraries when hiring DLns. The study recommended that the provided framework be adopted to guide library managers in identifying the needs of staff training and selecting the most adequate training method as well as settling on the best practices to be sent to staff for training and development.

Keywords: digital, academic, libraries, framework

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Authors: Daniel O. Wasonga, Jouko Kleemola, Laura Alakukku, Pirjo Makela

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Cassava (Manihot esculenta Crantz) is a major food crop for millions of people in the tropics. Growth and yield of cassava in the arid-tropics are seriously constrained by intermittent water deficit and low soil K content. Therefore, experiments were conducted to investigate the effects of interaction between water deficit and K fertigation on growth and yield response of biofortified cassava at early growth phase. Yellow cassava cultivar was grown under controlled glasshouse conditions in 5-L pots containing 1.7 kg of pre-fertilized potting mix. Plants were watered daily for 30 days after planting. Treatments were three watering levels (30%, severe water deficit; 60%, mild water deficit; 100%, well-watered), on which K (0.01, 1, 4, 16 and 32 mM) was split. Plants were harvested at 90 days after planting. Leaf area was smallest in plants grown with 30% watering and 0.01 mM K, and largest in plants grown with 100% watering and 32 mM K. Leaf, root, and total dry mass decreased in water-stressed plants. However, dry mass was markedly higher when plants were grown with 16 mM K under all watering levels in comparison to other K concentrations. The highest leaf, root and total dry mass were in plants with 100% watering and 16 mM K. In conclusion, K improved the growth of plants under water deficit and thus, K application on soils with low moisture and low K may improve the productivity of cassava.

Keywords: dry mass, interaction, leaf area, Manihot esculenta

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Authors: Vignesh Ratnaraj, Daniel Marascia, Kelly Ruecker

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Purpose: Pulmonary embolism (PE) is a major cause of morbidity and mortality in trauma patients. Data suggests PE is occurring earlier in trauma patients, with attention being turned to possible de novo events. Here, we examine the incidence of early PE at a level 1 trauma center and examine the relationship with a chest injury. Method: A retrospective analysis was performed from a prospective trauma registry at a level 1 trauma center. All patients admitted from 1 January 2010 to 30 June 2019 diagnosed with PE following trauma were included. Early PE was considered a diagnosis within 72 hours of admission. The severity of the chest injury was determined by the Abbreviated Injury Score (AIS). Analysis of severe chest injury and incidence of early PE was performed using chi-square analysis. Sub-analysis on the timing of PE and PE location was also performed using chi-square analysis. Results: Chest injury was present in 125 of 184 patients diagnosed with PE. Early PE occurred in 28% (n=35) of patients with a chest injury, including 24.39% (n=10) with a severe chest injury. Neither chest injury nor severe chest injury determined the presence of early PE (p= > 0.05). Sub-analysis showed a trend toward central clots in early PE (37.14%, n=13) compared to late (27.78%, n=25); however, this was not found to be significant (p= > 0.05). Conclusion: PE occurs early in trauma patients, with almost one-third being diagnosed before 72 hours. This analysis does not support the paradigm that chest injury, nor severe chest injury, results in statistically significant higher rates of early PE. Interestingly, a trend toward early central PE was noted in those suffering chest trauma.

Keywords: trauma, PE, chest injury, anticoagulation

Procedia PDF Downloads 72

Authors: Douglas N. Simões, Michele Pittol, Vanda F. Ribeiro, Daiane Tomacheski, Ruth M. C. Santana

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The increasing demand of thermoplastic elastomers is related to the wide range of applications, such as automotive, footwear, wire and cable industries, adhesives and medical devices, cell phones, sporting goods, toys and others. These materials are susceptible to microbial attack. Moisture and organic matter present in some areas (such as shower area and sink), provide favorable conditions for microbial proliferation, which contributes to the spread of diseases and reduces the product life cycle. Compounds based on SEBS copolymers, poly(styrene-b-(ethylene-co-butylene)-b-styrene, are a class of thermoplastic elastomers (TPE), fully recyclable and largely used in domestic appliances like bath mats and tooth brushes (soft touch). Zinc oxide and zinc ions loaded in personal and home care products have become common in the last years due to its biocidal effect. In that sense, the aim of this study was to evaluate the effect of zinc as antimicrobial agent in compounds based on SEBS/polypropylene/oil/ calcite for use as refrigerator seals (gaskets), bath mats and sink squeegee. Two zinc oxides from different suppliers (ZnO-Pe and ZnO-WR) and one masterbatch of zinc ions (M-Zn-ion) were used in proportions of 0%, 1%, 3% and 5%. The compounds were prepared using a co-rotating double screw extruder (L/D ratio of 40/1 and 16 mm screw diameter). The extrusion parameters were kept constant for all materials. Tests specimens were prepared using the injection molding machine. A compound with no antimicrobial additive (standard) was also tested. Compounds were characterized by physical (density), mechanical (hardness and tensile properties) and rheological properties (melt flow rate - MFR). The Japan Industrial Standard (JIS) Z 2801:2010 was applied to evaluate antibacterial properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The Brazilian Association of Technical Standards (ABNT) NBR 15275:2014 were used to evaluate antifungal properties against Aspergillus niger (A. niger), Aureobasidium pullulans (A. pullulans), Candida albicans (C. albicans), and Penicillium chrysogenum (P. chrysogenum). The microbiological assay showed a reduction over 42% in E. coli and over 49% in S. aureus population. The tests with fungi showed inconclusive results because the sample without zinc also demonstrated an inhibition of fungal development when tested against A. pullulans, C. albicans and P. chrysogenum. In addition, the zinc loaded samples showed worse results than the standard sample when tested against A. niger. The zinc addition did not show significant variation in mechanical properties. However, the density values increased with the rise in ZnO additives concentration, and had a little decrease in M-Zn-ion samples. Also, there were differences in the MFR results in all compounds compared to the standard.

Keywords: antimicrobial, home device, SEBS, zinc

Procedia PDF Downloads 287

Authors: Nwadike Emmanuel Chinagoron, Achebe Chukwunonso, Ezeliora Chukwuemeka Daniel, Azaka Onyemazuwa Andrew

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In this research work, the process of biodiesel production in a pilot plant was studied using cow tallow as raw material, methanol as the solvent and potassium hydroxide as catalysts. The biodiesel quality was determined by characterization. The tallow used in the production had a molecular weight of 860g. Its oil had a density value of 0.8g/ml, iodine value of 63.45, viscosity at 300C was 9.83pas, acid value was 1.96, free fatty acid (FFA) of 0.98%, saponification value of 82.75mleq/kg, specific gravity of 0.898, flash point of 1100C, cloud point of 950C and Calorific value also called Higher Heating Value (HHV) of 38.365MJ/Kg. The produced biodiesel had a density of 0.82g/ml, iodine value of 126.9, viscosity of 4.32pas at 300C, acid value of 0.561, FFA of 0.2805%, saponification value of 137.45 mleq/kg.Flash point, cloud point and centane number of the biodiesel produced are 1390C, 980C and 57.5 respectively, with fat content, protein content, ash content, moisture content, fiber content and carbohydrate content values of 10%, 2.8%, 5%, 5%, 20%, and 37.2% respectively. The biodiesel higher heating values (calorific values) when estimated from viscosity, density and flash points were 41.4MJ/Kg, 63.8MJ/Kg, and 34.6MJ/Kg respectively. The biodiesel was blended with conventional diesel. The blend B-10 had values of 1320C and 960C for flash and cloud points, with Calorific value (or HHV) of 34.6 MJ/Kg (when estimated from its Flash point) and fat content, protein content, ash content, moisture content, fiber content and carbohydrate content values of 5%, 2.1%,10%, 5%, 15%, and 62.9% respectively.

Keywords: biodiesel, characterization, cow-tallow, cetane rating

Procedia PDF Downloads 497

Authors: Daniel Fundi Murithi

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Missing data is a real bane in many surveys. To overcome the problems caused by missing data, partial deletion, and single imputation methods, among others, have been proposed. However, problems such as discarding usable data and inaccuracy in reproducing known population parameters and standard errors are associated with them. For regression and stochastic imputation, it is assumed that there is a variable with complete cases to be used as a predictor in estimating missing values in the other variable, and the relationship between the two variables is linear, which might not be realistic in practice. In this project, we estimate population total in presence of missing values in two-phase sampling. Instead of regression or stochastic models, non-parametric model based regression model is used in imputing missing values. Empirical study showed that nonparametric model-based regression imputation is better in reproducing variance of population total estimate obtained when there were no missing values compared to mean, median, regression, and stochastic imputation methods. Although regression and stochastic imputation were better than nonparametric model-based imputation in reproducing population total estimates obtained when there were no missing values in one of the sample sizes considered, nonparametric model-based imputation may be used when the relationship between outcome and predictor variables is not linear.

Keywords: finite population total, missing data, model-based imputation, two-phase sampling

Procedia PDF Downloads 100

Authors: Felipe M. de Freitas, Icaro V. Soares, Lucas L. L. Fortes, Sandro T. M. Gonçalves, Úrsula D. C. Resende

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The SPICE-based simulators are quite robust and widely used for simulation of electronic circuits, their algorithms support linear and non-linear lumped components and they can manipulate an expressive amount of encapsulated elements. Despite the great potential of these simulators based on SPICE in the analysis of quasi-static electromagnetic field interaction, that is, at low frequency, these simulators are limited when applied to microwave hybrid circuits in which there are both lumped and distributed elements. Usually the spatial discretization of the FDTD (Finite-Difference Time-Domain) method is done according to the actual size of the element under analysis. After spatial discretization, the Courant Stability Criterion calculates the maximum temporal discretization accepted for such spatial discretization and for the propagation velocity of the wave. This criterion guarantees the stability conditions for the leapfrogging of the Yee algorithm; however, it is known that for the field update, the stability of the complete FDTD procedure depends on factors other than just the stability of the Yee algorithm, because the FDTD program needs other algorithms in order to be useful in engineering problems. Examples of these algorithms are Absorbent Boundary Conditions (ABCs), excitation sources, subcellular techniques, grouped elements, and non-uniform or non-orthogonal meshes. In this work, the influence of the stability of the FDTD method in the modeling of concentrated elements such as resistive sources, resistors, capacitors, inductors and diode will be evaluated. In this paper is proposed, therefore, the electromagnetic modeling of electronic components in order to create models that satisfy the needs for simulations of circuits in ultra-wide frequencies. The models of the resistive source, the resistor, the capacitor, the inductor, and the diode will be evaluated, among the mathematical models for lumped components in the LE-FDTD method (Lumped-Element Finite-Difference Time-Domain), through the parametric analysis of Yee cells size which discretizes the lumped components. In this way, it is sought to find an ideal cell size so that the analysis in FDTD environment is in greater agreement with the expected circuit behavior, maintaining the stability conditions of this method. Based on the mathematical models and the theoretical basis of the required extensions of the FDTD method, the computational implementation of the models in Matlab® environment is carried out. The boundary condition Mur is used as the absorbing boundary of the FDTD method. The validation of the model is done through the comparison between the obtained results by the FDTD method through the electric field values and the currents in the components, and the analytical results using circuit parameters.

Keywords: hybrid circuits, LE-FDTD, lumped element, parametric analysis

Procedia PDF Downloads 118

Authors: Daniel K. Gameti

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The paper explored the effects of active and passive entrepreneurship education methods on the venture creation intention of undergraduate students in Ghana. The study also examined the moderating effect of gender and negative personal characteristics (risk tolerance, stress tolerance and fear of failure) on students’ venture creation intention. Deductive approach was used in collecting quantitative data from 555 business students from one public university and one private university through self-administered questionnaires. Descriptive statistic was used to determine the dominant method of entrepreneurship education used in Ghana. Further, structural equation model was used to test four hypotheses. The results of the study show that the dominant method of education used in Ghana was lectures and the least method used was field trip. The study further revealed that passive methods of education are less effective compared to active methods which were statistically significant in venture creation intention among students. There was also statistical difference between male and female students’ venture creation intention but stronger among male students and finally, the only personal characteristics that influence students’ intention was stress tolerance because risk tolerance and fear of failure were statistically insignificant.

Keywords: entrepreneurship education, Ghana, moderating variables, venture creation intention, undergraduate students

Procedia PDF Downloads 425