Search results for: controlled balanced boolean function

Authors: Mohamed Eftal Bin Mohamed Ebrahim, Alexander Varey

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Aim: Topical negative pressure has been shown to enhance angiogenesis during wound healing, both for open and closed wounds. Since angiogenesis is a key requirement for successful fat grafting, there may be a role for topical negative pressure as a means of enhancing the take rate during autologous fat grafting to breasts. Here we present a systematic review of the literature on this topic. Methods: Ovid and Embase were utilized, with searches ranging between 1960 – 2019. Terms (“Liposculpting” OR “Fat grafting” OR “Lipofilling” OR “Lipograft” OR “Fat transfer”) AND (“Negative Pressure” OR “Brava” OR “Kiwi”) AND (“Breast”) were merged as keywords. Inclusion criteria were females, autologous fat graft to breast with topical negative pressure prior to the procedure. Studies were excluded if there was no primary endpoint or non-original article. Results: Upon reviewing 219 articles, 2 met inclusion criteria. A total of 565 and 46 breasts in each article were treated respectively using the negative pressure device BRAVA®, with each cohort having different pre-and post-operative pressure settings. Khouri et al. cohort had higher graft survival (79%) compared to Del Vecchio et al. cohort (64%); however, the latter had fewer complications compared to Khouri’s cohort, e.g., fat necrosis, pneumothorax and infection. Conclusion: There is limited evidence regarding the use of topical negative pressure for fat grafting to the breasts. However, in the two studies published, the reported rates of success are high, suggesting there may be a benefit. Consequently, a randomized controlled trial on this area is required.

Keywords: fat grafting, lipograft, negative pressure, breast, breast augmentation, brava

Procedia PDF Downloads 196

Authors: M. Şahi̇n, E. Erdem, M. Saçak

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In this study, Na-smectite crystals purificated of bentonite were used after being swelling with benzyltributylammonium bromide (BTBAB) as alkyl ammonium salt. Swelling process was carried out using 0.2 g of BTBAB for smectite of 0.8 g with 4 h of mixing time after investigated conditions such as mixing time, the swelling agent amount. Then, the conductive poly(o-anisidine) (POA)/smectite nanocomposite was prepared in the presence of swollen Na-smectite using ammonium persulfate (APS) as oxidant in aqueous acidic medium. The POA content and conductivity of the prepared nanocomposite were systematically investigated as a function of polymerization conditions such as the treatment time of swollen smectite in monomer solution and o-anisidine/APS mol ratio. POA/smectite nanocomposite was characterized by XRD, FTIR and SEM techniques and was compared separately with components of composite.

Keywords: clay, composite, conducting polymer, poly(o-anisidine)

Procedia PDF Downloads 327

Authors: Jian Li

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Carotenoids area group of metabolites in mostly photosynthetic organisms such as plants and microalgae and have wide applications in cosmetics, food, feed, and health industries. Although phototrophic cultivation of microalgae has been developed to produce some carotenoids for decades, most carotenoids are currently synthesized chemically at industrial scales because of affordable production costs. Chemical carotenoids are regarded not as safe for human beings as natural carotenoids and are restricted only for animal feed markets, and the industries call for inexpensive sources of natural products. Microalgae grow much quicker in mixotrophy than in phototrophy, and thus mixotrophic cultivation processes have great potential to reduce the production cost of carotenoids from microalgae. However, much more expensive photobioreactor systems and more strictly controlled sterile processes are needed to avoid contamination by heterotrophic organisms during mixotrophic cultivation processes, which makes mixotrophy, in fact, much more expensive than phototrophic cultivation. Recently technical breakthroughs have been reported to overcome contamination problems in photobioreactor systems traditionally used for phototrophic cultivation, and a much lower process cost of mixotrophic cultivation than that of phototrophic cultivation might be achieved for carotenoid production. These reviews intend to summarize recent technical advancements in mixotrophic cultivation of microalgae, to evaluate the economic viability of carotenoid production from mixotrophically cultivated microalgae, and to prospect mixotrophy as a strategy to produce a variety of carotenoids for industrial applications.

Keywords: microalgae, carotenoid, mixotrophy, biotechnology

Procedia PDF Downloads 159

Authors: Lama Bendak

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Parents and teachers face major problems dealing with attention deficit hyperactivity students. One solution is by changing the school to a less restrictive one or leaving school for good. The purpose of this study is to highlight the importance and role of individual educational plans (IEP) in helping cycle one ages six to nine attention deficit hyperactivity disorder (ADHD) students on the behavioral level. We have adopted the qualitative approach experimental where the total number of the students in our field of study was 66 from four schools. We have limited our study to cycle one students; that is grades 1, 2 and 3, whose ages range from 5.5 to 8.5. We divided the students into two groups where the controlled group was 36 students, and the experimental group was 30 students. The measuring instrument or tool that we used in our study is The SNAP-IV Teacher and Parents Rating Scale and was filled by class teachers. We did the pretest during the first trimester of the school year. Then we applied the Individual Educational Plans IEP's for two trimesters. Then we did the posttest and submitted the results for analysis, where we used the ANCOVA. The results of this study showed that the IEP's efficacy in helping ADHD students on the behavioral aspect showed statistical differences and varied depending on the initial level of difficulty of the student.

Keywords: attention deficit hyperactivity disorder, individual educational plans, behavioral charts, SNAP-IV teacher and parents rating scale

Procedia PDF Downloads 287

Authors: Mamadou I. Wade, Henry C. Ogworonjo, Madiha Gul, Mandoye Ndoye, Mohamed Chouikha, Wayne Patterson

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In this paper, we present a novel application of the Paillier cryptographic system to the encryption of RGB (Red Green Blue) images. In this method, an RGB image is first separated into its constituent channel images, and the Paillier encryption function is applied to each of the channels pixel intensity values. Next, the encrypted image is combined and compressed if necessary before being transmitted through an unsecured communication channel. The transmitted image is subsequently recovered by a decryption process. We performed a series of security and performance analyses to the recovered images in order to verify their robustness to security attack. The results show that the proposed image encryption scheme produces highly secured encrypted images.

Keywords: image encryption, Paillier cryptographic system, RBG image encryption, Paillier

Procedia PDF Downloads 239

Authors: Ismail Okur, Betul Taspinar, Turkan Pasali Kilit, Eda O. Okur, Ferruh Taspinar

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Type 2 Diabetes Mellitus (T2DM) is one of the most important global health emergencies and every year more and more people are affected by T2DM. T2DM causes life-changing complications by affecting organ and systems. Although diet and exercise are the best way to treat patients with T2DM, those patients generally have a sedentary life style. This study was planned to determine whether patients with T2DM have kinesiophobia (fear of movement). A controlled trial was conducted on 87 adults. Forty-one individuals with T2DM (study group, 34 female and 7 male) and 46 nondiabetic individuals (control group, 39 female and 7 male) were included in the study. Patients were screened for fear of movement using the Tampa Scale for Kinesiophobia (TSK). The data including age, sex, weight, height, and TSK scores were obtained. Mann Whitney U test were used to analyse the data. The mean ages and BMI of study and control groups were 51.98 ± 6.03 year and 49.52 ± 5.61 year and 31.82 ± 2.88 kg/m2 and 30.22 ± 2.91 kg/m2, respectively. The groups have similar demographic properties. The kinesiophobia scores of study and control groups were 42.78 ± 5.50 and 39.48 ± 5.05, respectively and the difference was statistically significant (p=0.05). This study showed that patients with T2DM had high kinesiophobia scores rather than nondiabetics. Those patients might avoid to do exercise. In other words, patients with T2DM might have lower physical activity level. Therefore the authors suggest that to evaluate and interfere with kinesiophobia before conducting exercise therapy will be useful for diabetes care.

Keywords: diabetes, fear of movement, kinesiophobia, type 2 diabetes mellitus

Procedia PDF Downloads 379

Authors: G. La Scalia, M. Enea, R. Micale, O. Corona, L. Settanni

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The quality and condition of perishable products delivered to the market and their subsequent selling prices are directly affected by the care taken during harvesting and handling. Mechanical injury, in fact, occurs at all stages, from pre-harvest operations through post-harvest handling, packing and transport to the market. The main implications of this damage are the reduction of the product’s quality and economical losses related to the shelf life diminution. For most perishable products, the shelf life is relatively short and it is typically dictated by microbial growth related to the application of dynamic and static loads during transportation. This paper presents the correlation between vibration levels and microbiological growth on strawberries and woodland strawberries and detects the presence of volatile organic compounds (VOC) in order to develop an intelligent logistic unit capable of monitoring VOCs using a specific sensor system. Fresh fruits were exposed to vibrations by means of a vibrating table in a temperature-controlled environment. Microbiological analyses were conducted on samples, taken at different positions along the column of the crates. The values obtained were compared with control samples not exposed to vibrations and the results show that different positions along the column influence the development of bacteria, yeasts and filamentous fungi.

Keywords: microbiological analysis, shelf life, transport damage, volatile organic compounds

Procedia PDF Downloads 427

Authors: Christakis Damianou, Christos Christofi, Nicos Mylonas

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The aim of this paper was to conduct a feasibility study using a flat rectangular (3x10 mm2) MRI compatible transducer operating at 5 MHz for destroying atherosclerotic plaque using the thermal effects of ultrasound in in vitro models. A parametric study was performed where the time needed to ablate the plaque was studied as a function of Spatial Average Temporal Average (SATA) intensity, and pulse duration. The time needed to ablate plaque is directly related to intensity, and pulse duration. The temperature measured close to the artery is above safe limits and therefore thermal ultrasound does not have a place in removing plaques in arteries.

Keywords: ultrasound, atherosclerotic, plaque, pulse

Procedia PDF Downloads 295

Authors: R. O. Ocaya, J. J. Terblans

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The laws of Newtonian mechanics allow ab-initio molecular dynamics to model and simulate particle trajectories in material science by defining a differentiable potential function. This paper discusses some considerations for the coding of ab-initio programs for simulation on a standalone computer and illustrates the approach by C language codes in the context of embedded metallic atoms in the face-centred cubic structure. The algorithms use velocity-time integration to determine particle parameter evolution for up to several thousands of particles in a thermodynamical ensemble. Such functions are reusable and can be placed in a redistributable header library file. While there are both commercial and free packages available, their heuristic nature prevents dissection. In addition, developing own codes has the obvious advantage of teaching techniques applicable to new problems.

Keywords: C language, molecular dynamics, simulation, embedded atom method

Procedia PDF Downloads 306

Authors: M. Al Azri, M. Elzain, K. Bouziane, S. M. Chérif

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The electronic and magnetic properties of 6H-SiC with Mn impurities have been calculated using ab-initio calculations. Various configurations of Mn sites and Si and C vacancies were considered. The magnetic coupling between the two Mn atoms at substitutional and interstitials sites with and without vacancies is studied as a function of Mn atoms interatomic distance. It was found that the magnetic interaction energy decreases with increasing distance between the magnetic atoms. The energy levels appearing in the band gap due to vacancies and due to Mn impurities are determined. The calculated DOS’s are used to analyze the nature of the exchange interaction between the impurities. The band coupling model based on the p-d and d-d level repulsions between Mn and SiC has been used to describe the magnetism observed in each configuration. Furthermore, the impacts of applying U to Mn-d orbital on the magnetic moment have also been investigated. The results are used to understand the experimental data obtained on Mn- 6H-SiC (as-implanted and as –annealed) for various Mn concentration (CMn = 0.7%, 1.6%, 7%).

Keywords: ab-initio calculations, diluted magnetic semiconductors, magnetic properties, silicon carbide

Procedia PDF Downloads 294

Authors: Ziani Zakarya, Mahdad Moustafa Yassine

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Greenhouse farming has greatly contributed to the development of modern agriculture by optimizing crops, especially market gardening, ornamental horticulture, and recently, fruit species ... Greenhouse cultivation has enabled farmers to produce fruits and vegetables out of season while guaranteeing them a good production, and therefore a considerable gain throughout the year. However, this mode of production has shown its limits, especially in extreme conditions, such as the continental steppe climate and the Saharan climate, which are characterized by significant thermal amplitudes and strong winds, making it impossible to use conventional greenhouses for several months, of the year. In Algeria and precisely in the highlands, the use of greenhouses by farmers is very rare or occasional, especially in spring, because the limiting factors mentioned above are frequent there, causing significant damage to the plant product and to the environment. infrastructure. The same observation is observed in the Saharan regions but with less frequencies. Certainly, the use of controlled multi-chapel greenhouses would solve the problem, but at what cost? These hi-tech infrastructures are very expensive to purchase but also to maintain, so few farmers have the financial means to obtain them. In addition, the existence of intelligent and less expensive polymer films, whose properties could control greenhouse production parameters, in particular, the temperature parameter, maybe a judicious solution for the development of new generations of greenhouses that can be used in extreme conditions and normal.

Keywords: greenhouse, polymer film, modern agriculture, optimizing crops

Procedia PDF Downloads 181

Authors: J. Marx, D. Smazna, R. Adelung, B. Fiedler

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Aerographite is a 3D interconnected carbon foam. Its tetrapodal morphology is based on the zinc oxide (ZnO) template structure, which is replicated in the chemical vapour deposition (CVD) into a hollow carbon structure. This replication process is analyzed in ex-situ studies via interrupted synthesis and the observation of the reaction progress by using scanning electron (SEM), transmission electron microscopy (TEM) and Raman spectroscopy techniques. Based on the epitaxial growth process, with a layer-by-layer growth behaviour of the wall thickness or number of layers and the catalytical graphitization of the deposited amorphous carbon into graphitic carbon by zinc, a growth model is created. The properties of aerographite, such as the electrical conductivity is dependent on the graphitization and number of layer (wall thickness). Wall thicknesses between 3 nm and 22 nm are achieved by a controlled stepwise reduction of the synthesis time on the basis of the developed growth model, and by a further thermal treatment at 1800 °C the graphitization of the presented carbon foam is modified. The variation of the wall thickness leads to an optimum defect density (ID/IG ratio) and the graphitization to an improvement in the electrical conductivity. Furthermore, a metallic conducting behaviour of untreated and 1800 °C treated aerographite can be observed. Due to these structural and defective modifications, a fundamental structural-property equation for the description of their influences on the electrical conductivity is developed.

Keywords: electrical conductivity, electron microscopy (SEM/TEM), graphitization, wall thickness

Procedia PDF Downloads 156

Authors: Pujari Muruga, T. K. Radhakrishnan, N. Samsudeen

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Hydrogen is considered as the most important energy carrier and fuel of the future because of its high energy density and zero emission properties. Microbial Electrolysis Cell (MEC) is a new and promising approach for hydrogen production from organic matter, including wastewater and other renewable resources. By utilizing anode microorganism activity, MEC can produce hydrogen gas with smaller voltages (as low as 0.2 V) than those required for electrolytic hydrogen production ( ≥ 1.23 V). The hydrogen production processes of the MEC reactor are very nonlinear and highly complex because of the presence of microbial interactions and highly complex phenomena in the system. Increasing the hydrogen production rate and lowering the energy input are two important challenges of MEC technology. The mathematical model of the MEC is based on material balance with the integration of bioelectrochemical reactions. The main objective of the research is to produce biohydrogen by selecting the optimum current and controlling applied voltage to the MEC. Precise control is required for the MEC reactor, so that the amount of current required to produce hydrogen gas can be controlled according to the composition of the substrate in the reactor. Various simulation tests involving multiple set-point changes disturbance and noise rejection were performed to evaluate the performance using PID controller tuned with Ziegler Nichols settings. Simulation results shows that other good controller can provide better control effect on the MEC system, so that higher hydrogen production can be obtained.

Keywords: microbial electrolysis cell, hydrogen production, applied voltage, PID controller

Procedia PDF Downloads 249

Authors: Sajida Saqira, Anthony Chariton, Grant C. Hose

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The Anthropocene has seen dramatic environmental changes which are affecting every ecosystem on earth. Freshwater ecosystems are particularly vulnerable as they are at risk from the many activities that go on and contaminants that are released in catchments. They are thus subject to many stressors simultaneously. Freshwater ecosystems respond to stress at all levels of biological organization, from subcellular to community structure and ecosystem functioning. The aim of this study was to examine the resistance and resilience of freshwater ecosystems to multiple stressors. Here we explored the individual and combined effects of copper as a chemical stressor and common carp (Cyprinus carpio) as a biological stressor on the health, functioning, and recovery of outdoor experimental pond ecosystems in a long-term, controlled, factorial experiment. Primary productivity, decomposition, and water and sediment quality were analysed at regular intervals for one year to understand the health and functioning of the ecosystems. Changes to benthic biota were quantified using DNA-based and traditional microscopy-based counts of invertebrates. Carp were added to the ponds to copper contaminated sediments (with controls) to explore the combined effects of copper and carp and removed after six months to explore the resilience and recovery of the system. The outcomes of this study will advance our understanding of the impacts of multiple stressors on freshwater ecosystems, and the resilience of these systems to copper and C. carpio, which are both globally significant stressors in freshwater systems.

Keywords: carp, copper, ecosystem health, freshwater ecosystem, multiple stressors

Procedia PDF Downloads 124

Authors: M. Jerold, V. Sivasubramanian

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This study reports the removal of Malachite Green (MG) from simulated wastewater by using marine macro algae Ulva lactuca. Batch biosorption experiments were carried out to determine the biosorption capacity. The biosorption capacity was found to be maximum at pH 10. The effect of various other operation parameters such as biosorbent dosage, initial dye concentration, contact time and agitation was also investigated. The equilibrium attained at 120 min with 0.1 g/L of biosorbent. The isotherm experimental data fitted well with Langmuir Model with R² value of 0.994. The maximum Langmuir biosorption capacity was found to be 76.92 mg/g. Further, Langmuir separation factor RL value was found to be 0.004. Therefore, the adsorption is favorable. The biosorption kinetics of MG was found to follow pseudo second-order kinetic model. The mechanistic study revealed that the biosorption of malachite onto Ulva lactuca was controlled by film diffusion. The solute transfer in a solid-liquid adsorption process is characterized by the film diffusion and/or particle diffusion. Thermodynamic study shows ΔG° is negative indicates the feasibility and spontaneous nature for the biosorption of malachite green. The biosorbent was characterized using Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and elemental analysis (CHNS: Carbon, Hydrogen, Nitrogen, Sulphur). This study showed that Ulva lactuca can be used as promising biosorbent for the removal of MG from wastewater.

Keywords: biosorption, Ulva lactuca, wastewater, malachite green, isotherm, kinetics

Procedia PDF Downloads 157

Authors: Mohamamd Ayish

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This study addresses media diplomacy as an integral component of public diplomacy which emerged in the United States in the post-World War II era and found applications in other countries around the world. The study seeks to evolve a conceptual framework for understanding the practice of public diplomacy through social networks, often referred to as social engagement diplomacy. This form of diplomacy is considered far more ahead of the other two forms associated with both government controlled and independent media. The cases of the Voice of America Arabic Service and the 1977 CBS interviews with the late Egyptian President Anwar Sadat and Israeli Prime Minister Menachem Begin are cited in this study as reflecting the two traditional models. The new social engagement model sees public diplomacy as an act of communication that seeks to effect changes in target audiences through a process of persuasion shaped by discourse orientations and technological features. The proposed conceptual framework for social, diplomatic engagement draws on an open communication environment, an empowered audience, an interactive and symmetrical process of communication, multimedia-based flows of information, direct and credible feedback, distortion and high risk. The writer believes this study would be helpful in providing appropriate knowledge pertaining to our understanding of social diplomacy and furnishing concrete insights into how diplomats could harness virtual space to maximize their goals in the global environment.

Keywords: diplomacy, engagement, social, globalization

Procedia PDF Downloads 278

Authors: A. Rajabpour, A. Hadizadeh Kheirkhah

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Heat transfer is of great importance to biological systems in order to function properly. In the present study, specific heat capacity as one of the most important heat transfer properties is calculated for a soluble in water Lysozyme protein. Using equilibrium molecular dynamics (MD) simulation, specific heat capacities of pure water, dry lysozyme, and lysozyme-water solution are calculated at 300K for different weight fractions. It is found that MD results are in good agreement with ideal binary mixing rule at small weight fractions. Results of all simulations have been validated with experimental data.

Keywords: specific heat capacity, molecular dynamics simulation, lysozyme protein, equilibrium

Procedia PDF Downloads 309

Authors: Birge Yildirim Okta

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This paper aims to narrate the story of Atatürk Cultural Center in Taksim Square, which was demolished in 2018 and discuss its architectonic as a social place of memory and its existence and demolishment as the space of politics. The paper uses narrative discourse analysis to research Atatürk Cultural Center (AKM) as a place of memory and space of politics from the establishment of the Turkish Republic (1923) until today. After the establishment of the Turkish Republic, one of the most important implementations in Taksim Square, reflecting the internationalist style, was the construction of the Opera Building in Prost Plan. The first design of the opera building belonged to Aguste Perret, which could not be implemented due to economic hardship during World War II. Later the project was designed by architects Feridun Kip and Rüknettin Güney in 1946 but could not be completed due to the 1960 military coup. Later the project was shifted to another architect Hayati Tabanlıoglu, with a change in its function as a cultural center. Eventually, the construction of the building was completed in 1969 in a completely different design. AKM became a symbol of republican modernism not only with its modern architectural style but also with it is function as the first opera building of the Republic, reflecting the western, modern cultural heritage by professional groups, artists, and the intelligentsia. In 2005, Istanbul’s council for the protection of cultural heritage decided to list AKM as a grade 1 cultural heritage, ending a period of controversy which saw calls for the demolition of the center as it was claimed, it ended its useful lifespan. In 2008 the building was announced to be closed for repairs and restoration. Over the following years, the building was demolished piece by piece silently while the Taksim mosque has been built just in front of Atatürk Cultural Center. Belonging to the early republican period AKM was a representation of the cultural production of modern society for the emergence and westward looking, secular public space in Turkey. Its erasure from the Taksim scene under the rule of the conservative government, Justice, and Development Party, and the construction of the Taksim mosque in front of AKM’s parcel is also representational. The question of governing the city through space has always been an important aspect for governments, those holding political power since cities are the chaotic environments that are seen as a threat for the governments, carrying the tensions of the proletariat or the contradictory groups. The story of AKM as a dispositive or a regulatory apparatus demonstrates how space itself is becoming a political medium, to transform the socio-political condition. The paper narrates the existence and demolishment of the Atatürk Cultural Center by discussing the constructed and demolished building as a place of memory and space of politics.

Keywords: space of politics, place of memory, Atatürk Cultural Center, Taksim square, collective memory

Procedia PDF Downloads 145

Authors: Swapan Maiti, Dipanwita Roy Chowdhury

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Nonlinear functions are essential in different cryptoprimitives as they play an important role on the security of the cipher designs. Rule 30 was identified as a powerful nonlinear function for cryptographic applications. However, an attack (MS attack) was mounted against Rule 30 Cellular Automata (CA). Nonlinear rules as well as maximum period CA increase randomness property. In this work, nonlinear rules of maximum period nonlinear hybrid CA (M-NHCA) are studied and it is shown to be a better crypto-primitive than Rule 30 CA. It has also been analysed that the M-NHCA with single nonlinearity injection proposed in the literature is vulnerable against MS attack, whereas M-NHCA with multiple nonlinearity injections provide maximum length cycle as well as better cryptographic primitives and they are also secure against MS attack.

Keywords: cellular automata, maximum period nonlinear CA, Meier and Staffelbach attack, nonlinear functions

Procedia PDF Downloads 316

Authors: Hariti Rafika, Fekih Malika, Saighi Mohamed

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Heat transfer by natural convection in storage tanks for LNG is extremely related to heat gains through the walls with thermal insulation is not perfectly efficient. In this paper, we present the study of natural convection in the unsteady regime for natural gas in aware phase using the fluent software. The gas is just on the surface of the liquid phase. The CFD numerical method used to solve the system of equations is based on the finite volume method. This numerical simulation allowed us to determine the temperature profiles, the stream function, the velocity vectors and the variation of the heat flux density in the vapor phase in the LNG storage tank volume. The results obtained for a general configuration, by numerical simulation were compared to those found in the literature.

Keywords: numerical simulation, natural convection, heat gains, storage tank, liquefied natural gas

Procedia PDF Downloads 438

Authors: Tayyaba Ghani, Mazhar Mehmood, Mohammad Mujahid

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TiO₂ nanotubes are receiving immense attraction in the field of dye-sensitized solar cells due to their well-defined nanostructures, efficient electron transport and large surface area as compared to other one dimensional structures. In the present work, we have investigated the influence of temperature on the morphology of anodically produced self-organized Titanium oxide nanotubes (TiNTs). TiNTs are synthesized by two-step anodization method in an ethylene glycol based electrolytes containing ammonium fluoride. Experiments are performed at constant anodization voltage for two hours. An investigation by the SEM images reveals that if the temperature is kept constant during the anodizing experiment, variation in the average tube diameter is significantly reduced. However, if the temperature is not controlled then due to the exothermic nature of reactions for the formation of TiNTs, the temperature of electrolyte keep on increasing. This variation in electrolyte bath temperature introduced strong variations in tube diameter (20 nm to 160 nm) along the length of tubes. Current profiles, recorded during the anodization experiment, predict the effect of constant and varying experimental temperatures as well. In both cases, XRD results show the complete anatase crystal structure of nanotube upon annealing at 450 °C. Present work highlights the importance of constant temperature during the anodization experiments in order to develop an ordered array of nanotubes with a uniform tube diameter.

Keywords: anodization, ordering, temperature, TiO₂ nanotubes

Procedia PDF Downloads 172

Authors: F. Louati, H. Trabelsi, M. Jamei

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Desiccation cracks following drainage-humidification cycles. With water loss, mainly due to evaporation, suction in the soil increases, producing volumetric shrinkage and tensile stress. When the tensile stress reaches tensile strength, the soil cracks. Desiccation cracks networks can directly control soil hydraulic properties. The aim of this study was for quantifying the hydraulic properties for examples the water retention curve, the saturated hydraulic conductivity, the unsaturated hydraulic conductivity function, the shrinkage dynamics in Tibar soil- clay soil in the Northern of Tunisia. Then a numerical simulation of unsaturated hydraulic properties for a crack network has been attempted. The finite elements code ‘CODE_BRIGHT’ can be used to follow the hydraulic distribution in cracked porous media.

Keywords: desiccation, cracks, permeability, unsaturated hydraulic flow, simulation

Procedia PDF Downloads 301

Authors: Mohamed Habila, Ahmed Mohamed El-Toni, Mohamed Sheikh Moshab, Abdulrhman Al-Awadi, Zeid AL Othman

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Water pollution with dyes is a critical environmental issue because off the huge amount of dyes disbarred annually, which cause severe damage for the ecosystem and human life. The main raison for this severs pollution is the rapid industrial development which led to more production of harmful pollutants. on the other hand, the core shell based magnetic materials have showed amazing character for controlling the material synthesis with the targeted structure to enhance the adsorptive removal of pollutants. Herein, the Fe3O4core-meso SiO2/TiO2 double shell have been prepared for methylene blue dye adsorption. the preparation procedure is controlled to prepare the magnetic core with further coating layers from silica and titania. The prepared Fe3O4core-meso SiO2/TiO2 double shell showed adsorption capacity for methylene blue removal about 50 mg/g at pH 6 after 80 min contact time form 50 ppm methylene blue solution. The adsorption process of methylene blue onto Fe3O4core-meso SiO2/TiO2 double shell was well fitted with the pseudo-second-order kinetic model and freundlish isotherm, indicating a quick and multilayer adsorption mechanism.

Keywords: magnetic core, silica shell, titania shell, water treatment, methylene blue, solvo-thermal process, adsorption

Procedia PDF Downloads 127

Authors: Ayalew Tadese Kibret, Belayneh Sisay Alemu, Amare Kassaw Yimer

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Intelligent reflecting surfaces (IRSs) are considered to be a key enabling technology for sixth-generation (6G) wireless networks. IRSs are electromagnetic (EM) surfaces that are fabricated and have integrated electronics, electronically controlled processes, and particularly wireless communication features. IRSs operate without the need for complex signal processing and the encoding and decoding steps that improve the signal quality at the receiver. Improving vital performance parameters such as energy efficiency (EE) and spectral efficiency (SE) have frequently been the primary goals of research in order to meet the increasing requirements for advanced services in the future 6G communications. In this research, we conduct a comparative analysis on single and multi-IRS wireless communication networks using energy and spectrum efficiency. The energy efficiency versus user distance, energy efficiency versus signal to noise ratio, and spectral efficiency versus user distance are the basis for our result with 1, 2, 4, and 6 IRSs. According to the results of our simulation, in terms of energy and spectral efficiency, six IRS perform better than four, two, and single IRS. Overall, our results suggest that multi-IRS-assisted wireless communication systems outperform single IRS systems in terms of communication performance.

Keywords: sixth-generation (6G), wireless networks, intelligent reflecting surfaces, energy efficiency, spectral efficiency

Procedia PDF Downloads 29

Authors: Arvind Salem

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Voters across the country are transferring the power of redistricting from the state legislatures to commissions to secure “fairer” districts by curbing the influence of gerrymandering on redistricting. Gerrymandering, intentionally drawing distorted districts to achieve political advantage, has become extremely prevalent, generating widespread voter dissatisfaction and resulting in states adopting commissions for redistricting. However, the efficacy of these commissions is dubious, with some arguing that they constitute a panacea for gerrymandering, while others contend that commissions have relatively little effect on gerrymandering. A result showing that commissions are effective would allay these fears, supplying ammunition for activists across the country to advocate for commissions in their state and reducing the influence of gerrymandering across the nation. However, a result against commissions may reaffirm doubts about commissions and pressure lawmakers to make improvements to commissions or even abandon the commission system entirely. Additionally, these commissions are publicly funded: so voters have a financial interest and responsibility to know if these commissions are effective. Currently, nine states place commissions in charge of redistricting, Arizona, California, Colorado, Michigan, Idaho, Montana, Washington, and New Jersey (Hawaii also has a commission but will be excluded for reasons mentioned later). This study compares the degree of gerrymandering in the 2022 election (“after”) to the election in which voters decided to adopt commissions (“before”). The before-election provides a valuable benchmark for assessing the efficacy of commissions since voters in those elections clearly found the districts to be unfair; therefore, comparing the current election to that one is a good way to determine if commissions have improved the situation. At the time Hawaii adopted commissions, it was merely a single at-large district, so it is before metrics could not be calculated, and it was excluded. This study will use three methods to quantify the degree of gerrymandering: the efficiency gap, the percentage of seats and the percentage of votes difference, and the mean-median difference. Each of these metrics has unique advantages and disadvantages, but together, they form a balanced approach to quantifying gerrymandering. The study uses a Wilcoxon Signed-Rank Test with a null hypothesis that the value of the metrics is greater than or equal to after the election than before and an alternative hypothesis that the value of these metrics is greater in the before the election than after using a 0.05 significance level and an expected difference of 0. Accepting the alternative hypothesis would constitute evidence that commissions reduce gerrymandering to a statistically significant degree. However, this study could not conclude that commissions are effective. The p values obtained for all three metrics (p=0.42 for the efficiency gap, p=0.94 for the percentage of seats and percentage of votes difference, and p=0.47 for the mean-median difference) were extremely high and far from the necessary value needed to conclude that commissions are effective. These results halt optimism about commissions and should spur serious discussion about the effectiveness of these commissions and ways to change them moving forward so that they can accomplish their goal of generating fairer districts.

Keywords: commissions, elections, gerrymandering, redistricting

Procedia PDF Downloads 73

Authors: Katsumi Hirata

Abstract:

Certain systems can function well only if they recognize the sound environment as humans do. In this research, we focus on sound classification by adopting a convolutional neural network and aim to develop a method that automatically classifies various environmental sounds. Although the neural network is a powerful technique, the performance depends on the type of input data. Therefore, we propose an approach via a slice bispectrogram, which is a third-order spectrogram and is a slice version of the amplitude for the short-time bispectrum. This paper explains the slice bispectrogram and discusses the effectiveness of the derived method by evaluating the experimental results using the ESC‑50 sound dataset. As a result, the proposed scheme gives high accuracy and stability. Furthermore, some relationship between the accuracy and non-Gaussianity of sound signals was confirmed.

Keywords: environmental sound, bispectrum, spectrogram, slice bispectrogram, convolutional neural network

Procedia PDF Downloads 128

Authors: Qimin Shi, Yi Sun, Constantinus Politis, Shoufeng Yang

Abstract:

In-situ preparation of particle-reinforced aluminium matrix composites (PRAMCs) by laser powder bed fusion (LPBF) additive manufacturing is a promising strategy to strengthen traditional Al-based alloys. The laser-driven thermite reaction can be a practical mechanism to in-situ synthesize PRAMCs. However, introducing oxygen elements through adding Fe₂O₃ makes the powder mixture highly sensitive to form porosity and Al₂O₃ film during LPBF, bringing challenges to producing dense Al-based materials. Therefore, this work develops a processing strategy combined with consecutive high-energy laser melting scanning and low-energy laser remelting scanning to prepare PRAMCs from a Fe₂O₃/AlSi12 powder mixture. The powder mixture consists of 5 wt% Fe₂O₃ and the remainder AlSi12 powder. The addition of 5 wt% Fe₂O₃ aims to achieve balanced strength and ductility. A high relative density (98.2 ± 0.55 %) was successfully obtained by optimizing laser melting (Emelting) and laser remelting surface energy density (Eremelting) to Emelting = 35 J/mm² and Eremelting = 5 J/mm². Results further reveal the necessity of increasing Emelting, to improve metal liquid’s spreading/wetting by breaking up the Al₂O₃ films surrounding the molten pools; however, the high-energy laser melting produced much porosity, including H₂₋, O₂₋ and keyhole-induced pores. The subsequent low-energy laser remelting could close the resulting internal pores, backfill open gaps and smoothen solidified surfaces. As a result, the material was densified by repeating laser melting and laser remelting layer by layer. Although with two-times laser scanning, the microstructure still shows fine cellular Si networks with Al grains inside (grain size of about 370 nm) and in-situ nano-precipitates (Al₂O₃, Si, and Al-Fe(-Si) intermetallics). Finally, the fine microstructure, nano-structured dispersion strengthening, and high-level densification strengthened the in-situ PRAMCs, reaching yield strength of 426 ± 4 MPa and tensile strength of 473 ± 6 MPa. Furthermore, the results can expect to provide valuable information to process other powder mixtures with severe porosity/oxide-film formation potential, considering the evidenced contribution of laser melting/remelting strategy to densify material and obtain good mechanical properties during LPBF.

Keywords: densification, laser powder bed fusion, metal matrix composites, microstructures, mechanical properties

Procedia PDF Downloads 156

Authors: Marlin Killen

Abstract:

The American Association of University Professors (AAUP) describes academic freedom as essential to the purposes of research and teaching. The importance of academic freedom as a bedrock foundation that supports the work of the professoriate cannot be overstated, and there have been innumerable challenges that have attempted to curtail it. These challenges come from a variety of sources that span legal, ethical, cultural, institutional, and professional perspective and are amplified by social media, traditional media, and political action efforts. Because of these challenges, the development of a comprehensive institutional policy on academic freedom that addresses the principles, practices, and appropriate responses to modern challenges can be a daunting task. This presentation will focus on a case study of a university’s effort to develop an updated, evolving policy on academic freedom that provides a framework and remedies for contemporary challenges to this critical function in higher education.

Keywords: academic freedom, academic freedom policy, higher education policy

Procedia PDF Downloads 202

Authors: Yang Zhong, Meijie Xu

Abstract:

The explicit solutions for the natural frequencies and mode shapes of the orthotropic rectangular plate with four clamped edges are presented by the double finite cosine integral transform method. In the analysis procedure, the classical orthotropic rectangular thin plate is considered. Because only are the basic dynamic elasticity equations of the orthotropic thin plate adopted, it is not need prior to select the deformation function arbitrarily. Therefore, the solution developed by this paper is reasonable and theoretical. Finally, an illustrative example is given and the results are compared with those reported earlier. This method is found to be easier and effective. The results show reasonable agreement with other available results, but with a simpler and practical approach.

Keywords: rectangular orthotropic plate, four clamped edges, natural frequencies and mode shapes, finite integral transform

Procedia PDF Downloads 578

Authors: Chinh Nguyen Nhu Bao, Hien To Thi, Norimichi Takenaka

Abstract:

Formaldehyde (HCHO) concentrations in rainwater including in tropical storms in Sakai City, Osaka, Japan have been measured continuously during rain event by developed chemiluminescence method. The level of formaldehyde was ranged from 15 µg/L to 500 µg/L. The high concentration of HCHO in rainwater is related to the wind direction from the south and west sides of Sakai City where manufactures related to chemicals, oil-refinery, and steel. The in-situ irradiated experiment on rainwater sample was conducted to prove the aqueous phase photo-production of HCHO and the degradation of HCHO. In the daytime, the aqueous phase photolysis is the source of HCHO in rainwater (4.52 ± 5.74 µg/L/h for UV light source in-situ condition, 2.84-8.96 µg/L/h under sunlight). However, in the night time, the degradation is the function of microorganism.

Keywords: chemiluminescence, formaldehyde, rainwater, typhoon

Procedia PDF Downloads 166