Search results for: DC-DC power conversion

Authors: Y. Benabid, K. Benfriha, V. Rieuf, J. F. Omhover

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This paper describes an approach to create custom concepts for innovative products; this approach describes relations between innovation tools and Computer Aided Design environment (use creativity session and design tools). A model for the design process is proposed and explored in order to describe the power tool used to create and ameliorate an innovative product all based upon a range of data (cloud points) in this study. Comparison between traditional method and innovative method we help to generate and put forward a new model of the design process in order to create a custom Ankle Foot Orthosis (AFO) in a CAD environment in order to ameliorate and controlling the motion. The custom concept needs big development in different environments; the relation between these environments is described. The results can help the surgeons in the upstream treatment phases. CAD models can be applied and accepted by professionals in the design and manufacture systems. This development is based on the anatomy of the population of North Africa.

Keywords: ankle foot orthosis, CAD, reverse engineering, sketch

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Authors: C. G. Jinimole, A. Harsha

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One of the key problems facing in the analysis of Computed Tomography (CT) images is the poor contrast of the images. Image enhancement can be used to improve the visual clarity and quality of the images or to provide a better transformation representation for further processing. Contrast enhancement of images is one of the acceptable methods used for image enhancement in various applications in the medical field. This will be helpful to visualize and extract details of brain infarctions, tumors, and cancers from the CT image. This paper presents a comparison study of five contrast enhancement techniques suitable for the contrast enhancement of CT images. The types of techniques include Power Law Transformation, Logarithmic Transformation, Histogram Equalization, Contrast Stretching, and Laplacian Transformation. All these techniques are compared with each other to find out which enhancement provides better contrast of CT image. For the comparison of the techniques, the parameters Peak Signal to Noise Ratio (PSNR) and Mean Square Error (MSE) are used. Logarithmic Transformation provided the clearer and best quality image compared to all other techniques studied and has got the highest value of PSNR. Comparison concludes with better approach for its future research especially for mapping abnormalities from CT images resulting from Brain Injuries.

Keywords: computed tomography, enhancement techniques, increasing contrast, PSNR and MSE

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Authors: Leone Sherman

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While the democratic rights of a citizen may be very clearly outlined in a country’s constitution, it’s not uncommon for political elite to undermine those rights and gain more power and control over a country than it is allowed by this constitution. Moreover, while such a change in some smaller states may not have a substantial impact on the international community, the same change in countries with vast resources and political influence, such as Russia, is always a considerable factor for the world policy. This article aims to research the weaknesses of the Russian democratic system and their effect on the international policy through the three key aspects: The Russian people’s ability to produce the required political will to control their government’s decisions, the current development of the Russian political environment, and the affection of this environment on the world community as a whole during the recent years. The used methodology is a narrative analysis of recent political events, official statistics, international investigations and media statements. As a result, the ever-widening gap between the people and the government becomes evidently seen, as well as the challenges it imposes on the political world arena, both current and those that still lie ahead of us.

Keywords: Russia, political analysis, democratic weaknesses, international society

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Authors: Adeyemi Kamil Hamzah, Abayomi Nathaniel Oyesikun

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Throughout modern history internal strife has burdened Africa most populous nation, Nigeria. The country encompassed more than four hundred ethnic and sub ethnic groups with the different background and identities. This group has not fussed themselves together to emerge as a nation what we have are mere ethnic and religious groups i.e. Hausa/Fulani Igbo Yoruba Ijaw, Ibibio, christian, and Muslim. The source of problematic Nigeria is linked to colonial policy of segmentation, discontent to religion, faith, and ethnicity. The wave of spiral killing among the major ethnic entities with different religious affiliation has brought the process of good governance in the country to its kneel. This paper will place insecurity in Nigeria in context by reviewing the root and rise of ethnic militia. In doing so it will evaluate how the West Africa power house arrive at the point where it is today with all unprecedented unrest from regions that formed Nigeria. Both primary and secondary sources were applied for the quality of this paper. The effects of ethnic militia in realizing and actualizing political stability are equally discussed, recommendations proffered and conclusion given.

Keywords: ethnic, militia, violence, insecurity, democracy

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Authors: Mishak Rahul, Naveen Kumar, Bharath Kumar

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Conceived as a high-end engine to revolutionise sustainable agri-food production, the intelligent crop circle (ICC) aims to incorporate the Internet of Things (IoT), blockchain technology and artificial intelligence (AI) to bolster resource efficiency and prevent waste, increase the volume of production and bring about sustainable solutions with long-term ecosystem conservation as the guiding principle. The operating principle of the ICC relies on bringing together multidisciplinary bottom-up collaborations between producers, researchers and consumers. Key elements of the framework include IoT-based smart sensors for sensing soil moisture, temperature, humidity, nutrient and air quality, which provide short-interval and timely data; blockchain technology for data storage on a private chain, which maintains data integrity, traceability and transparency; and AI-based predictive analysis, which actively predicts resource utilisation, plant growth and environment. This data and AI insights are built into the ICC platform, which uses the resulting DSS (Decision Support System) outlined as help in decision making, delivered through an easy-touse mobile app or web-based interface. Farmers are assumed to use such a decision-making aid behind the power of the logic informed by the data pool. Building on existing data available in the farm management systems, the ICC platform is easily interoperable with other IoT devices. ICC facilitates connections and information sharing in real-time between users, including farmers, researchers and industrial partners, enabling them to cooperate in farming innovation and knowledge exchange. Moreover, ICC supports sustainable practice in agriculture by integrating gamification techniques to stimulate farm adopters, deploying VR technologies to model and visualise 3D farm environments and farm conditions, framing the field scenarios using VR headsets and Real-Time 3D engines, and leveraging edge technologies to facilitate secure and fast communication and collaboration between users involved. And through allowing blockchain-based marketplaces, ICC offers traceability from farm to fork – that is: from producer to consumer. It empowers informed decision-making through tailor-made recommendations generated by means of AI-driven analysis and technology democratisation, enabling small-scale and resource-limited farmers to get their voice heard. It connects with traditional knowledge, brings together multi-stakeholder interactions as well as establishes a participatory ecosystem to incentivise continuous growth and development towards more sustainable agro-ecological food systems. This integrated approach leverages the power of emerging technologies to provide sustainable solutions for a resilient food system, ensuring sustainable agriculture worldwide.

Keywords: blockchain, internet of things, artificial intelligence, decision support system, virtual reality, gamification, traceability, sustainable agriculture

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Authors: Hamid Aslani, Ahmed Radwan

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In this paper, a single element microstrip antenna is presented for UWB applications by using techniques as partial ground plane and modified the shape of the patch. The antenna is properly designed to have a compact size and constant gain against frequency. The simulated results have done using two EM software and show good agreement with the measured results for the fabricated antenna. Then a designing of two elements patch antenna array for UWB in the frequency band of 3.1-10 GHz is presented in this paper. The array is constructed by means of feeding two omni-directional modified circular patch elements with a modified power divider. Experimental results show that the array has a stable radiation pattern and low return loss over a broad bandwidth of 64% (3.1–10 GHz). Due to its planar profile, physically compact size, wide impedance bandwidth, directive performance over a wide bandwidth proposed antenna is a good candidate for portable UWB applications and other UWB integrated circuits.

Keywords: ultra wide band, radiation performance, microstrip antenna, size miniaturized antenna

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Authors: Arya Pirooz

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The effects of different fuels (DME, RME B100, and SME B100) on barrel engines were studied as a general, single dimensional investigation for characterization of these types of engines. A base computational model was created as reference point to be used as a point of comparison with different cases. The models were computed using the commercial computational fluid dynamics program, Diesel-RK. The base model was created using basic dimensions of the PAMAR-3 engine with inline unit injectors. Four fuel cases were considered. Optimized models were also considered for diesel and DME cases with respect to injection duration, fuel, injection timing, exhaust and intake port opening, CR, angular offset. These factors were optimized for highest BMEP, combined PM and NOx emissions, and highest SFC. Results included mechanical efficiency (eta_m), efficiency and power, emission characteristics, combustion characteristics. DME proved to have the highest performing characteristics in relation to diesel and RME fuels for this type of barrel engine.

Keywords: DME, RME, Diesel-RK, characterization, inline unit injector

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Authors: Victoria Scarratt

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Couples involved in age-gap relationships generally evoke negative stereotypes, opinions, and social disapproval. This research seeks to examine whether financial disparities in age-discrepant relationships cause negative attitudes in study participants. It was hypothesized that an age-gap couple (29 year difference) would receive a greater degree of societal disapproval when the couple also had a large salary gap compared to a similarly aged couple (1 year difference) with a salary gap. Additionally, there would be no significant difference between age-gap couples without a salary-gap compared to a similarly aged couple without a salary gap. To test the hypothesis, participants were given one of four scenarios regarding a couple in a romantic relationship.Then they were asked to respond to nine Likert scale questions. Results indicated that participants perceived age-gap relationships with a salary disparity to be less equitable in regard to a power imbalance between the couple and the financial and general gain that one partner will receive. A significant interaction was also detected for evoking feelings of disgust in participants and how morally correct it is for the couple to continue their relationship.

Keywords: age gap relationships, love, financial disparities, societal stigmas, relationship dynamics

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Authors: Kaushalendra Kumar, Abhishek Kumar, Chandra Moni, Sanjay Kumar, P. K. Singh, Ajeet Kumar

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Present study investigated the dietary inclusion of Moringa oleifera leaf meal (MOLM) on production efficiency, hemato-biochemical profile and economy of Vanaraja birds under tropical condition. Experiment was conducted for a period of 56 days on 300 Vanaraja birds randomly divided in to five different experimental groups including control of 60 birds each group replicated with 20 chicks in each replicate. T1, T2, T3, T4, and T5 were offered with 0, 5, 10, 15, and 20% Moringa oleifera leaf meal along with basal ration. All the standard managemental practices were followed during experimental period including vaccination schedule. Locally available Moringa oleifera leaves were harvested at mature stage and allowed to dry under shady and aerated conditions. Thereafter, dried leaves were milled to make a leaf meal and stored in the airtight nylon bags to avoid any possible contamination from foreign material and use for experiment. Production parameters were calculated based on the amount of feed consumed and weight gain every weeks. The body weight gain of T2 group was significantly (P < 0.05) higher side whereas T3 group was comparable with control. The feed conversion ratio for T2 group was found to be significantly (P < 0.05) lower than all other treatment groups, while none of the group was comparable with each other. At the end of the experiment blood samples were collected from birds for haematology study while serum biochemistry performed using spectrophotometer following statndard protocols. The haematological attributes were significantly (P > 0.05) not differed among the groups. However, serum biochemistry showed significant reduction (P < 0.05) of blood urea nitrogen, uric acid and creatinine level with higher level of MOLM diet, indicates better utilization of protein supplemented through MOLM. The total cholesterol and triglyceride level was declined significantly (P < 0.05) as compare to control group with increased level of MOLM in basal diet, decreasing trend of serum cholesterol noted. However, value of HDL for T3 group was highest and for T1 group was lowest but no significant difference (P < 0.05) found among the groups. It might be due to presence of β-sitosterol a bioactive compound present in MOLM which causes lowering of plasma concentration of LDL. During experiment total, LDL and VLDL level was found to be decreased significantly (P < 0.05) as compare to control group. It was observed that the production efficiency of birds significantly improved with 5% followed by 10% Moringa oleifera leaf meal among the treatment groups. However, the maximum profit per kg live weight was noted in 10 % level and least profit observed in 20% MOLM fed group. It was concluded that the dietary inclusion of MOLM improved overall performances without affecting metabolic status and effective in reducing cholesterol level reflects healthy chicken production for human consumption.

Keywords: hemato biochemistry, Moringa oleifera leaf meal, performance, Vanaraja birds

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Authors: Aghoutane Basma, Naama Amal, Talbi Hayat, El Manfalouti Hanae, Kartah Badreddine

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Aromatic and medicinal plants are used by man for different needs, including food and medicinal needs for their biological properties attributed mainly to phenolic compounds and for their antioxidant capacity. In our study, the aim is to compare three extraction solvents by evaluating the contents of phenolic compounds, the contents of flavonoids, and the antioxidant activities of extracts from different methods of extracting the aerial part of an endemic medicinal plant from Morocco. This activity was also confirmed by three methods (2,2-diphenyl-1-picrylhydrazyl (DPPH), antioxidant reducing power of iron (FRAP), and total antioxidant capacity (CAT)). The results showed that this plant is rich in polyphenols and flavonoids, as well as it has a very important antioxidant capacity in whatever the solvent or the extraction method. This suggests the importance of using extracts from this plant as a new natural source of food additives and potent antioxidants in the food industry.

Keywords: endemic plant of Morocco, phenolic compound, solvent, extraction technique, antioxidant activity

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Authors: Ugochukwu D. Abasilim, Aize I. Obayan, Adedayo J. Odukoya, Godwyns Agube, Power A. I. Wogu, Nchekwube Excellence-Oluye

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This paper examines the effect of transformational leadership style on organizational commitment among Private University employees in Nigeria. A quantitative methodology was adopted for this study. A structured Multi-factor Leadership Questionnaire (MLQ) developed by Bass and Avolio (1997) and Organizational Commitment Questionnaire (OCQ) developed by Meyer and Allen (1997) were the major instruments used for data collection. Simple linear regression was used for testing the hypothesis. The results indicated that there was no significant positive effect of transformational leadership style on organizational commitment among employees of the Nigerian private university studied. Though the respondents rated their leaders high on transformational leadership style, their organizational commitment rating was average for majority, which implies that employees’ level of commitment could be accounted for by transformational leadership style existing in the institution. This finding is antithetical to the common submission in literature that transformational leadership style has a significant effect on organizational commitment. It was therefore recommended that further studies may want to further explore the reasons for this variance.

Keywords: leadership style, Nigeria, organizational, commitment, transformational leadership

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Authors: Henni Mansour Abdelwaheb

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This study discusses the design of a bounded position/force feedback controller developed to ensure position and force tracking for bilateral teleoperation arms operating with variable delay, and actuator saturation. Also, an adaptive robust Radial Basis Function (RBF) neural network is used to estimate the environment torque. The parameters of the environment torque are then sent from the slave site to the master site as a non-power signal to avoid passivity problems. Moreover, a nonlinear function is applied to each controller term as a smooth saturation function, providing a bounded control signal and preserving the system’s actuators. Lastly, the Lyapunov approach demonstrates the global stability of the controlled system, and numerical experiment results further confirm the validity of the presented strategy.

Keywords: teleoperation manipulators system, time-varying delay, actuator saturation, adaptive robust rbf neural network approximation, uncertainties

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Authors: Carlos Minguez, Christian F. Sagbay, Erika E. Ordoñez

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Guinea pigs (Cavia porcellus) play prominent roles as experimental models for medical research and as pets. However, in developing countries like South America, the Philippines, and sub-Saharan Africa, the meat of guinea pigs is an economic source of animal protein for the poor and malnourished humans because guinea pigs are mainly fed with forage and do not compete directly with human beings for food resources, such as corn or wheat. To achieve efficient production of guinea pigs, it is essential to provide insurance against vitamin C deficiency. The objective of this research was to investigate the effect of the partial replacement of alfalfa with fresh citrus pulp (Citrus sinensis) in a diet of guinea pigs on the growth performance, slaughter traits and mortality during the fattening period (between 20 and 74 days of age). A total of 300 guinea pigs were housed in collective cages of about ten animals (2 x 1 x 0.4 m) and were distributed into two completely randomized groups. Guinea pigs in both groups were fed ad libitum, with a standard commercial pellet diet (10 MJ of digestible energy/kg, 17% crude protein, 11% crude fiber, and 4.5% crude fat). Control group was supplied with fresh alfalfa as forage. In the treatment group, 30% of alfalfa was replaced by fresh citrus pulp. Growth traits, including body weight (BW), average daily gain (ADG), feed intake (FI), and feed conversion ratio (FCR), were measured weekly. On day 74, the animals were slaughtered, and slaughter traits, including live weight at slaughter (LWS), full gastrointestinal tract weight (FGTW), hot carcass weight (with head; HCW), cold carcass weight (with head; CCW), drip loss percentage (DLP) and dressing out carcass yield percentage (DCY), were evaluated. Contrasts between groups were obtained by calculated generalized least squares values. Mortality was evaluated by Fisher's exact test due to low numbers in some cells. In the first week, there were significant differences in the growth traits BW, ADG, FI, and FCR, which were superior in control group. These differences may have been due to the origin of the young guinea pigs, which, before weaning, were all raised without fresh citrus pulp, and they were not familiarized with the new supplement. In the second week, treatment group had significantly increased ADG compared with control group, which may have been the result of a process of compensatory growth. During subsequent weeks, no significant differences were observed between animals raised in the two groups. Neither were any significant differences observed across the total fattening period. No significant differences in slaughter traits or mortality rate were observed between animals from the two groups. In conclusion, although there were no significant differences in growth performance, slaughter traits, or mortality, the use of fresh citrus pulp is recommended. Fresh citrus pulp is a by-product of orange juice industry and it is cheap or free. Forage made with fresh citrus pulp could reduce about of 30 % the quantity of alfalfa in guinea pig for meat and as consequence, reduce the production costs.

Keywords: fresh citrus, growth, Guinea pig, mortality

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Authors: Farhana Tarannum

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Ambient (outdoor) air pollution is now recognized as an important problem, both nationally and worldwide. The concentrations of gaseous pollutants (SOx, NOx, CO and O3) have been determined from samples collected at Kallyanpur along Shamoli corridor in Dhaka city. Pollutants were determined in a sample collected at ground level and a roof of a 7-storied building. These pollutants are emitted largely from stationary sources like fossil fuel fired power plants, industrial plants, and manufacturing facilities as well as mobile sources. The incomplete combustion of fuel, wood and the Sulphur containing fuel used in the vehicles are one of the main causes of CO and SOx respectively in our natural environment. When the temperature of combustion in high enough and some of that nitrogen reacts with oxygen in the air, various nitrogen oxides (NOx) are then formed. The VOCs react with NOx in the presence of sunlight to form O3. UV Visible spectrophotometric method has been used for the determination of SOx, NOx and O3. The sensor type device was used for the estimation of CO. It was found that the air pollutants (CO, SOx, NOx and O3) of a sample collected at the roof of a building were lower compared to the ground level; it indicated that ground level people are mostly affected by the gaseous pollutants.

Keywords: gaseous pollutants, UV-visible spectrophotometry, ambient air quality, Dhaka city

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Authors: Saurabh Chanana, Monika Arora

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Demand response is getting increased attention these days due to the increase in electricity demand and introduction of renewable resources in the existing power grid. Traditionally demand response programs involve large industrial consumers but with technological advancement, demand response is being implemented for small residential and commercial consumers also. In this paper, demand response program aims to reduce the peak demand as well as overall energy consumption of the residential customers. Air conditioners are the major reason of peak load in residential sector in summer, so a dynamic model of air conditioning load with thermostat action has been considered for applying demand response programs. A programmable communicating thermostat (PCT) is a device that uses real time pricing (RTP) signals to control the thermostat setting. A new model incorporating PCT in air conditioning load has been proposed in this paper. Results show that introduction of PCT in air conditioner is useful in reducing the electricity payments of customers as well as reducing the peak demand.

Keywords: demand response, home energy management, programmable communicating thermostat, thermostatically controlled appliances

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Authors: Taboka Motlhabane, Pradeep Sahoo

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The global demand for cooling has grown exponentially over the past century to meet economic development and social needs, accounting for approximately 10% of the global electricity consumption. As global temperatures continue to rise, the demand for cooling and heating, ventilation and air-conditioning (HVAC) equipment is set to rise with it. The increased use of HVAC equipment has significantly contributed to the growth of greenhouse gas (GHG) emissions which aid the climate crisis- one of the biggest challenges faced by the current generation. The need to address emissions caused directly by HVAC equipment and electricity generated to meet the cooling or heating demand is ever more pressing. Currently, developed countries account for the largest cooling and heating demand, however developing countries are anticipated to experience a huge increase in population growth in 10 years, resulting in a shift in energy demand. Developing countries, which are projected to account for nearly 60% of the world's GDP by 2030, are rapidly building infrastructure and economies to meet their growing needs and meet these projections. Cooling, a very energy-intensive process that can account for 20 % to 75% of a building's energy, depending on the building's use. Solar photovoltaic (PV) driven air-conditioning offers a great cost-effective alternative for adoption in both residential and non-residential buildings to offset grid electricity, particularly in countries with high irradiation, such as Botswana. This research paper explores the potential of a grid-connected solar photovoltaic vapor-compression air-conditioning system for the Peter-Smith herbarium at the Okavango Research Institute (ORI) University of Botswana campus in Maun, Botswana. The herbarium plays a critical role in the collection and preservation of botanical data, dating back over 100 years, with pristine collection from the Okavango Delta, a UNESCO world heritage site and serves as a reference and research site. Due to the herbarium’s specific needs, it operates throughout the day and year in an attempt to maintain a constant herbarium temperature of 16°?. The herbarium model studied simulates a variable-air-volume HVAC system with a system rating of 30 kW. Simulation results show that the HVAC system accounts for 68.9% of the building's total electricity at 296 509.60 kWh annually. To offset the grid electricity, a 175.1 kWp nominal power rated PV system requiring 416 modules to match the required power, covering an area of 928 m2 is used to meet the HVAC system annual needs. An economic assessment using PVsyst found that for an installation priced with average solar PV prices in Botswana totalled to be 787 090.00 BWP, with annual operating costs of 30 500 BWP/year. With self-project financing, the project is estimated to have recouped its initial investment within 6.7 years. At an estimated project lifetime of 20 years, the Net Present Value is projected at 1 565 687.00 BWP with a ROI of 198.9%, with 74 070.67 tons of CO2 saved at the end of the project lifetime. This study investigates the performance of the HVAC system to meet the indoor air comfort requirements, the annual PV system performance, and the building model has been simulated using DesignBuilder Software.

Keywords: vapor compression refrigeration, solar cooling, renewable energy, herbarium

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Authors: Luke Andrighetto, Paul G. Stevenson, Luke C. Henderson, Jim Pearson, Xavier A. Conlan

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As pseudoephedrine, a common ingredient in cold and flu medications is closely monitored and restricted in Australia, alternative methods of accessing it are of interest. The impurities and by-products of every reaction step of pseudoephedrine/ephedrine and methamphetamine synthesis have been mapped in order to develop a chemical fingerprint based on synthetic route. Likewise, seized methamphetamine contains a combination of different cutting agents and starting materials. Therefore, in-silico optimised two-dimensional HPLC with DryLab® and OpenMS® software has been used to efficiently separate complex seizure samples. An excellent match between simulated and real separations was observed. Targeted separation of model compounds was completed with significantly reduced method development time. This study produced a two-dimensional separation regime that offers unprecedented separation power (separation space) while maintaining a rapid analysis time that is faster than those previously reported for gas chromatography, single dimension high performance liquid chromatography or capillary electrophoresis.

Keywords: chemical fingerprint, ephedrine, methamphetamine, two-dimensional HPLC

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Authors: Leslie Raphael de M. Ferraz, Salvana Priscylla M. Costa, Tarcyla de A. Gomes, Giovanna Christinne R. M. Schver, Cristóvão R. da Silva, Magaly Andreza M. de Lyra, Danilo Augusto F. Fontes, Larissa A. Rolim, Amanda Carla Q. M. Vieira, Miracy M. de Albuquerque, Pedro J. Rolim-Neto

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Efavirenz (EFV) is a drug used as first-line treatment of AIDS. However, it has poor aqueous solubility and wettability, presenting problems in the gastrointestinal tract absorption and bioavailability. One of the most promising strategies to improve the solubility is the use of solid dispersions (SD). Therefore, this study aimed to characterize SD EFZ with the polymers: PVP-K30, PVPVA 64 and SOLUPLUS in order to find an optimal formulation to compose a future pharmaceutical product for AIDS therapy. Initially, Physical Mixtures (PM) and SD with the polymers were obtained containing 10, 20, 50 and 80% of drug (w/w) by the solvent method. The best formulation obtained between the SD was selected by in vitro dissolution test. Finally, the drug-carrier system chosen, in all ratios obtained, were analyzed by the following techniques: Differential Scanning Calorimetry (DSC), polarization microscopy, Scanning Electron Microscopy (SEM) and spectrophotometry of absorption in the region of infrared (IR). From the dissolution profiles of EFV, PM and SD, the values of area Under The Curve (AUC) were calculated. The data showed that the AUC of all PM is greater than the isolated EFV, this result is derived from the hydrophilic properties of the polymers thus favoring a decrease in surface tension between the drug and the dissolution medium. In adittion, this ensures an increasing of wettability of the drug. In parallel, it was found that SD whom had higher AUC values, were those who have the greatest amount of polymer (with only 10% drug). As the amount of drug increases, it was noticed that these results either decrease or are statistically similar. The AUC values of the SD using the three different polymers, followed this decreasing order: SD PVPVA 64-EFV 10% > SD PVP-K30-EFV 10% > SD Soluplus®-EFV 10%. The DSC curves of SD’s did not show the characteristic endothermic event of drug melt process, suggesting that the EFV was converted to its amorphous state. The analysis of polarized light microscopy showed significant birefringence of the PM’s, but this was not observed in films of SD’s, thus suggesting the conversion of the drug from the crystalline to the amorphous state. In electron micrographs of all PM, independently of the percentage of the drug, the crystal structure of EFV was clearly detectable. Moreover, electron micrographs of the SD with the two polymers in different ratios investigated, we observed the presence of particles with irregular size and morphology, also occurring an extensive change in the appearance of the polymer, not being possible to differentiate the two components. IR spectra of PM corresponds to the overlapping of polymer and EFV bands indicating thereby that there is no interaction between them, unlike the spectra of all SD that showed complete disappearance of the band related to the axial deformation of the NH group of EFV. Therefore, this study was able to obtain a suitable formulation to overcome the solubility limitations of the EFV, since SD PVPVA 64-EFZ 10% was chosen as the best system in delay crystallization of the prototype, reaching higher levels of super saturation.

Keywords: characterization, dissolution, Efavirenz, solid dispersions

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Authors: S. O. Oyamakin, A. U. Chukwu,

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We proposed a Hyperbolic Gompertz Growth Model (HGGM), which was developed by introducing a stabilizing parameter called θ using hyperbolic sine function into the classical gompertz growth equation. The resulting integral solution obtained deterministically was reprogrammed into a statistical model and used in modeling the height and diameter of Pines (Pinus caribaea). Its ability in model prediction was compared with the classical gompertz growth model, an approach which mimicked the natural variability of height/diameter increment with respect to age and therefore provides a more realistic height/diameter predictions using goodness of fit tests and model selection criteria. The Kolmogorov-Smirnov test and Shapiro-Wilk test was also used to test the compliance of the error term to normality assumptions while using testing the independence of the error term using the runs test. The mean function of top height/Dbh over age using the two models under study predicted closely the observed values of top height/Dbh in the hyperbolic gompertz growth models better than the source model (classical gompertz growth model) while the results of R2, Adj. R2, MSE, and AIC confirmed the predictive power of the Hyperbolic Monomolecular growth models over its source model.

Keywords: height, Dbh, forest, Pinus caribaea, hyperbolic, gompertz

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Authors: Sajjad Shalsouz, Hamid karamipour

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Islamic civilization after a period of glory in the ninth and tenth centuries AD, known as the Islamic Renaissance, stagnated and declined from the eleventh century, despite the political and military power of Islamic governments, faced a scientific and cultural decline in later, foreign invaders such as the Mongol invasion, the Crusades, and Timur invasions also caused severe political, social, and economic instability, some of which were never remedied. Lack of growth of intellectual sciences in Islamic societies, which is necessary for the growth and development of any civilization, and lack of attention of the ruling class and the masses to this important factor, the tyranny of kings, social and economic turmoil from the thirteenth century onwards, absence of Islamic societies from global developments all intensified and stabilized the decline Islamic civilizations, the consequences of which are still evident. This article tries to deal with the historical factors of this decline and decadence from the 11th century to the contemporary era by examining historical events and issues and achieves a desirable and efficient result in this field.

Keywords: Islamic civilization, decline, historical factors, intellectual sciences

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Authors: A. G. Back

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Urban planning is a relevant tool to address, in a systemic way, several sectoral policies capable of linking the urban agenda with the reduction of socio-environmental risks. The Sao Paulo’s master plan (2014) presents innovations capable of promoting the transition to sustainability in the urban space, with a view to its regulatory instruments related to i) promotion of density in the axes of mass transport involving the mixture of commercial, residential, services, and leisure uses (principles related to the compact city); ii) vulnerabilities reduction based on housing policies including regular sources of funds for social housing and land reservation in urbanized areas; iii) reserve of green areas in the city to create parks and environmental regulations for new buildings focused on reducing the effects of heat island and improving urban drainage. However, its long-term implementation involves distributive conflicts and can undergo changes in different political, economic, and social contexts over time. Thus, the main objective of this paper is to identify and analyze the dynamics of conflicts of interest between social groups in the implementation of Sao Paulo’s urban development policy, particularly in relation to recent attempts at a (re) interpretation of the Master Plan guidelines, in view of the proposals for revision of the urban zoning law. In this sense, we seek to identify the demands, narratives of urban actors, including the real estate market, middle-class neighborhood associations ('not in my backyard' movements), and social housing rights movements. And we seek to analyze the power resources that these actors mobilize to influence the decision-making process, involving five categories: social capital, political access; discursive resource; media, juridical resource. The major findings of this research suggest that the interests and demands of the real estate market do not always prevail in urban regulation. After all, other actors also press for the definition of urban law with interests opposite to those of the real estate market. This is the case of associations of middle-class neighborhoods, which work to protect the characteristics of the locality, acting, in general, to prevent constructive and population densification in neighborhoods well located near the center, in São Paulo. One of the main demands of these “not in my backyard” movements is the delimitation of exclusively residential areas in the central region of the city, which is not only contrary to the interests of the real state market but also contrary to the principles of the compact city. On the other hand, social housing rights movements have also made progress in delimiting special areas of social interest in well-located and valued areas in the city dedicated to building social housing, also contrary to the interests of the real estate market. An urban development that follows the principles of the compact city must take into account the insertion of low-income populations in well-located regions; otherwise, such a development model may continue to push the less favored to the peripheries towards the preservation areas and/or risk areas.

Keywords: interest groups, Sao Paulo, sustainable urban development, urban policies implementation

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Authors: Riyad Awad, Abdulmohsen Alghadeer, Meshari Otaibi

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Proper operation and maintenance (O&M) activities of high voltage equipment can lead to an increased asset lifecycle and maintain its integrity and reliability. Such a vital process is important to be proactively considered during equipment design and manufacturing phases by removing and eliminating any obstacles in the equipment which adversely affect the (O&M) activities. This paper presents a gap analysis pertaining to difficulties in performing operations and maintenance (O&M) high voltage electrical equipment, includes power transformers, switch gears, motor control center, disconnect switches and circuit breakers. The difficulties are gathered from field personnel, equipment design review comments, quality management system, and lessons learned database. The purpose of the gap analysis is to mitigate and prevent the (O&M) difficulties as early as possible in the design stage of the equipment lifecycle. The paper concludes with several recommendations and corrective actions for all identified gaps in order to reduce the cost (O&M) difficulties and improve the equipment lifecycle.

Keywords: operation and maintenance, high voltage equipment, equipment lifecycle, reduce the cost of maintenance

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Authors: Virender Ranga, Mayank Dave, Anil Kumar Verma

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Recently wireless sensor networks (WSNs) are used in many real life applications like environmental monitoring, habitat monitoring, health monitoring etc. Due to power constraint cheaper devices used in these applications, the energy consumption of each device should be kept as low as possible such that network operates for longer period of time. One of the techniques to prolong the network lifetime is an intelligent grouping of sensor nodes such that they can perform their operation in cooperative and energy efficient manner. With this motivation, we propose a novel approach by organize the sensor nodes in cooperative multihop mini-groups so that the total global energy consumption of the network can be reduced and network lifetime can be improved. Our proposed approach also reduces the number of transmitted messages inside the WSNs, which further minimizes the energy consumption of the whole network. The experimental simulations show that our proposed approach outperforms over the state-of-the-art approach in terms of stability period and aggregated data.

Keywords: clustering, cluster-head, mini-group, stability period

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Authors: Brandon To, Yong S. Park

Abstract:

As more battery electric vehicles are being introduced into the automobile industry, continuous advancements are constantly made in the electric vehicle space. Improvements in lithium-ion battery technology allow electric vehicles to be capable of traveling long distances. The batteries are capable of being charged faster, allowing for a sufficient range in shorter amounts of time. With increased reliance on battery technology and the changes in vehicle power trains, new challenges arise from this. Resulting electric vehicle fires caused by collisions are potentially more dangerous than those of the typical internal combustion engine. To further reduce the battery failures involved with side collisions, this project intends to reinforce an existing battery pack of an electric vehicle with honeycomb structures such that intrusion into the batteries can be minimized with weight restrictions in place. Honeycomb structures of hexagonal geometry are implemented into the side extrusions of the battery pack. With the use of explicit dynamics simulations performed in ANSYS, quantitative results such as deformation, strain, and stress are used to compare the performance of the battery pack with and without the implemented honeycomb structures.

Keywords: battery pack, electric vehicle, honeycomb, side impact

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Authors: Josselyn Mata Calidonio, Arianna I. Maddox, Kimberly Hamad-Schifferli

Abstract:

Rapid diagnostics are critical infectious disease tools that are designed to detect a known biomarker using antibodies specific to that biomarker. However, a way to detect unknown viruses has not yet been achieved in a paper test format. We describe here a route to make an adaptable paper immunoassay that can detect an unknown biomarker, demonstrating it on SARS-CoV-2 variants. The immunoassay repurposes cross-reactive antibodies raised against the alpha variant. Gold nanoparticles of two different colors conjugated to two different antibodies create a colorimetric signal, and machine learning of the resulting colorimetric pattern is used to train the assay to discriminate between variants of alpha and Omicron BA.5. By using principal component analysis, the colorimetric test patterns can pick up and discriminate an unknown that it has not encountered before, Omicron BA.1. The test has an accuracy of 100% and a potential calculated discriminatory power of 900. We show that it can be used adaptively and that it can be used to pick up emerging variants without the need to raise new antibodies.

Keywords: adaptive immunoassay, detecting unknown viruses, gold nanoparticles, paper immunoassay, repurposing antibodies

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Authors: Ahmed H. Abdullah, Pavel Kroupa

Abstract:

Globular clusters (GC) are important objects for tracing the early evolution of a galaxy. We study the correlation between the cluster population and the global properties of the host galaxy. We found that the correlation between cluster population (NGC) and the baryonic mass (Mb) of the host galaxy are best described as 10 −5.6038Mb. In order to understand the origin of the U -shape relation between the GC specific frequency (SN) and Mb (caused by the high value of SN for dwarfs galaxies and giant ellipticals and a minimum SN for intermediate mass galaxies≈ 1010M), we derive a theoretical model for the specific frequency (SNth). The theoretical model for SNth is based on the slope of the power-law embedded cluster mass function (β) and different time scale (Δt) of the forming galaxy. Our results show a good agreement between the observation and the model at a certain β and Δt. The model seems able to reproduce higher value of SNth of β = 1.5 at the midst formation time scale.

Keywords: galaxies: dwarf, globular cluster: specific frequency, number of globular clusters, formation time scale

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Authors: Anil Kawan, Soon Jae Yu, Jong Min Park

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GaN-based 365 nm wavelength ultraviolet (UV) light emitting diodes (LED) have various applications: curing, molding, purification, deodorization, and disinfection etc. However, their usage is limited by very low output power, because of the light absorption in the GaN layers. In this study, we demonstrate a method utilizing removal of 365 nm absorption layer buffer GaN and thinning the n-type GaN so as to improve the light extraction efficiency of the GaN-based 365 nm UV LED. The UV flip chip LEDs of chip size 1.3 mm x 1.3 mm were fabricated using GaN epilayers on a sapphire substrate. Via-hole n-type contacts and highly reflective Ag metal were used for efficient light extraction. LED wafer was aligned and bonded to AlN carrier wafer. To improve the extraction efficiency of the flip chip LED, sapphire substrate and absorption layer buffer GaN were removed by using laser lift-off and dry etching, respectively. To further increase the extraction efficiency of the LED, exposed n-type GaN thickness was reduced by using inductively coupled plasma etching.

Keywords: extraction efficiency, light emitting diodes, n-GaN thinning, ultraviolet

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Authors: Babatope Alabadan, Adeyinka Adesanya, I. E. Afangideh

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The use of energy is paramount to human existence. Every activity globally revolves round it. Over the years, different sources of energy (petroleum fuels predominantly) have been utilized. Animal waste treatment on the farm is a phenomenon that has called for rapt research attention. Generated wastes on farm pollute the environment in diverse ways. Waste-to-bioenergy treatments can provide livestock operators with multiple value-added, renewable energy products. The objective of this work is to generate methane (CH4) gas from the anaerobic digestion of piggery dung. A retention time of 15 and 30 days and a mesophilic temperature range were selected. The generated biogas composition was methane (CH4), carbondioxide (CO2), hydrogen sulphide (H2S) and ammonia (NH3) using gas chromatography method. At 15 days retention time, 60% of (CH4) was collected while CO2 and traces of H2S and NH3 accounted for 40%. At 30 days retention time, 75% of CH4, 20% of CO2 was collected while traces of H2S and NH3 amounted to 5%. For on and off farm uses, biogas can be upgraded to biomethane by removing the CO2, NH3 and H2S. This product (CH4) can meet heating and power needs or serve as transportation fuels

Keywords: anaerobic digestion, biogas, methane, piggery dung

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Authors: S. O. Uwaifo

Abstract:

The paper examines the pivotal role of the library in university education through the provision of a wide range of information materials (print and non- print) required for the teaching, learning and research activities of the university. However certain impediments to the effectiveness of Nigerian university libraries, such as financial constraints, high foreign exchange, global disparities in accessing the internet, lack of local area networks, erratic electric power supply, absence of ICT literacy, poor maintenance culture, etc., were identified. Also, the necessity of repositioning Nigerian university libraries for effective information provision and delivery was stressed by pointing out their dividends, such as users’ access to Directory of Open Access Journals (DOAJ), Online Public Access Catalogue (OPAC), Institutional Repositories, Electronic Document Delivery, Social Media Networks, etc. It therefore becomes necessary for the libraries to be repositioned by way of being adequately automated or digitized for effective service delivery, in this age of globalization. Based on the identified barriers by this paper, some recommendations were proffered.

Keywords: repositioning, Nigerian university libraries, effective information provision and delivery, globalization

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Authors: Dechrit Maneetham

Abstract:

The aim of this paper was to design a void and head controlled electric power wheelchair (EPW). A novel activate the control system for quadriplegics with voice, head and neck mobility. Head movement has been used as a control interface for people with motor impairments in a range of applications. Acquiring measurements from the module is simplified through a synchronous a motor. Axis measures the two directions namely x and y. At the same time, patients can control the motorized wheelchair using voice signals (forward, backward, turn left, turn right, and stop) given by it self. The model of a dc motor is considered as a speed control by selection of a PID parameters using genetic algorithm. An experimental set-up constructed, which consists of micro controller as controller, a DC motor driven EPW and feedback elements. This paper is tuning methods of parameter for a pulse width modulation (PWM) control system. A speed controller has been designed successfully for closed loop of the dc motor so that the motor runs very closed to the reference speed and angle. Intelligent wheelchair can be used to ensure the person’s voice and head are attending the direction of travel asserted by a conventional, direction and speed control.

Keywords: wheelchair, quadriplegia, rehabilitation , medical devices, speed control

Procedia PDF Downloads 519