Nonlinear and sampled data control with application to power systems

Sampled data systems have come into practical importance for a variety of reasons. The earliest of these had primarily to do with economy of design. A more recent surge of interest was due to increase utilization of digital computers as controllers in feedback systems. This thesis contributes some control design for a class of nonlinear system exhibition linear output. The solution of several nonlinear control problems required the cancellation of some intrinsic dynamics (so-called zero dynamics) of the plant under feedback. It results that the so-dened control will ensure stability in closed-loop if and only if the dynamics to cancel are stable. What if those dynamics are unstable? Classical control strategies through inversion might solve the problem while making the closed loop system unstable. This thesis aims to introduce a solution for such a problem. The main idea behind our work is to stabilize the nonminimum phase system in continuous- time and undersampling using zero dynamics concept. The overall work in this thesis is divided into two parts. In Part I, we introduce a feedback control designs for the input-output stabilization and the Disturbance Decoupling problems of Single Input Single Output nonlinear systems. A case study is presented, to illustrate an engineering application of results. Part II illustrates the results obtained based on the Articial Intelligent Systems in power system machines. We note that even though the use of some of the AI techniques such as Fuzzy Logic and Neural Network does not require the computation of the model of the application, but it will still suer from some drawbacks especially regarding the implementation in practical applications. An alternative used approach is to use control techniques such as PID in the approximated linear model. This design is very well known to be used, but it does not take into account the non-linearity of the model. In fact, it seems that control design that is based on nonlinear control provide better performances

Use of alginate/montmorillonite nanocomposites as drug delivery system for curcumin

Curcumin (Cur.) is a well known traditional medicine due to its anti-inflammatory and antioxidant properties. Its pharmacological mechanism of action and safety have been extensively studied to investigate its use in clinical and therapeutic applications. However, its low water solubility and rapid metabolism are main obstacles. Different techniques were used to overcome the drawbacks of curcumin, with recent attention focusing on approaches based on nanotechnology. Clay-polymer nanocomposites are getting to play a role in nanoformulations for drug delivery. This is due to their improved rheological and mechanical properties, and controlled drug release characteristics compared to their individual components, clays and polymers. Alginate/ montmorillonite (MMT) nanocomposites are used as drug delivery system for a wide variety of drugs due to numerous advantages of both components such as the high loading capacity of MMT and the ability of alginate release encapsulated drugs in a controlled manner. Accordingly, this study aimed at the preparation of curcumin loaded alginate/MMT nanocomposites and the investigation of their release properties. Exfoliated MMT clay was first prepared by stirring the clay in an aqueous suspension for 4 hours, followed by filtration and drying at 70 °C. Exfoliation was confirmed by X-ray diffraction (XRD) and Fourier Transform infrared (FTIR) spectroscopy. Curcumin loaded MMT was then prepared by dispersing the exfoliated clay into an ethanoic curcumin solution. Different parameters were tested, namely stirring time, curcumin solution concentration and ratio of MMT to curcumin, in order to find out the maximum loading conditions. Stirring exfoliated MMT into curcumin solution of 1 mg/ml for 1 hour and in 5% W/V ratio was found to be the best condition for maximum loading (6.56 mg/g, corresponding to entrapment efficiency of 25.62 %). The hybrid sample (curcumin loaded MMT) was thus prepared. Visible spectrophotometric measurements of the curcumin solution were used to determine the amount of curcumin loaded by measuring the absorbance of curcumin solution before and after the dispersion of the clay. The hybrid sample was then encapsulated into alginate beads with different hybrid to alginate ratios (W/W) using the ionotropic technique. XRD and FTIR analysis were used for the characterization of the prepared hybrid and nanocomposites. They revealed the increase in the degree of clay exfoliation upon drug loading and encapsulation into the alginate beads and the loss of the crystalline nature of curcumin upon v adsorption onto the clay surface without any chemical interaction between the clay and curcumin. The release of curcumin from different alginate/MMT nanocomposites was studied in different biorelevent media: fast gastric (FaSSGF), fast intestinal (FaSSIF) and fed intestinal media (FeSSIF). The curcumin release in gastric media was negligible and this was attributed to its low solubility in these media and to the shrinkage of alginate beads in the acidic pH environment. Curcumin release in intestinal media was significantly higher and was found to be affected by both the feeding state and the ratio of hybrid to alginate. Increasing the hybrid to alginate ratio decreased the percentage of curcumin release because of the decrease of the swelling ratio of alginate due to the crosslinking effect of the clay. Consequently, the 1:20 (W/W) hybrid to alginate ratio nanocomposite sample (NC 1) showed the highest release percentage in both fast and fed intestinal media (71% in the FaSSIF and 15.5 % in the FeSSIF). On the other hand, the 1:2 (W/W) hybrid to alginate ratio nanocomposite sample (NC 4) demonstrated the lowest release percentage in both media (17.4% in FaSSIF and 6.6 % in FeSSIF). The feeding state played additional role in the percentage of curcumin released as it was found to affect both the pH and the concentration of the natural solubilizing components such as phospholipids and bile salts of the intestine. Accordingly, the percentage of curcumin released was higher in the fasting state than in the fed state due to the higher pH of the former media (88.4% in the FaSSIF and 16.6% in the FeSSIF for NC 1. Curcumin release in both intestinal media demonstrated different behaviors: in FaSSIF sustained release behavior was found to occur for 24 hours, while curcumin release reached a plateau by 8 hours in the FeSSIF. This study reveals the promising use of alginate/MMT nanocomposites as sustained release drug delivery system for curcumin through surface adsorption of curcumin onto the surface of exfoliated clay and encapsulation of the loaded clay into alginate beads. The release of curcumin would be hindered into the gastric environment and start into the intestine. For maximum and sustained release behavior a fasting state is preferred

Aneurysms in pediatric age: A challenging and rare disease entity

Introduction Pediatric arterial aneurysms are extremely rare. Their etiology can be congenital, mycotic, following infective endocarditis, post-traumatic pseudoaneurysms, or vasculitis. The treatment strategy in children is not very clear because of the small number of cases.Methods This study included eight children with arterial aneurysms, which included one thoracic, two abdominal aortic, one iliac, three upper-extremity, and two carotid aneurysms. Revascularization was performed using an autogenous vein whenever feasible. Anastomoses were performed with interrupted sutures with nonabsorbable material to allow for future growth of the vessels. Ligation was allowed only after ensuring that the distal collateral circulation was adequate.Results Eight aneurysms were reconstructed and one carotid aneurysm was ligated. No neurologic events occurred after the carotid ligation. Follow-up ranged between 4 months and 4 years and showed no recurrences or occlusion of reconstructed  aneurysms, as detected clinically and radiologically. The grafts used for reconstruction – including the synthetic ones – were found to be growing with the age of the children. In one aortic case, there was mild stenosis in one of the iliac limbs, but that was asymptomatic. The extremity aneurysms repair were uneventful, with good flow in the affected extremity.Conclusion Repair of aneurysms in children is feasible and yields good midterm results. Management is usually individual and tailored to each case. Finding the suitable conduit is a challenge, and autogenous veins are preferred whenever  available.Keywords: aneurysm, aorta, mycotic, pediatri

Effects of Escapin Intermediate Products (EIP-K) on Biofilms of Pseudomonas aeruginosa

Escapin is an L-amino acid oxidase that produces antimicrobial metabolites collectively called “Escapin Intermediate Products” (EIP-K). EIP-K and H2O2 together were previously shown to be bactericidal towards diverse planktonic bacteria. The present work investigates the ability of EIP-K and H2O2 to antagonize bacterial biofilms, using Pseudomonas aeruginosa as a model. The project had three aims: 1) determine the most effective concentrations of EIP-K and H2O2 necessary to break down existing P. aeruginosa biofilms, using a crystal violet assay; 2) examine the ability of EIP-K + H2O2 to inhibit biofilm formation, using triphenyl tetrazolium chloride dye; and 3) determine the effect of EIP-K + H2O2 on the viability, biomass and structure of biofilms cultivated in flow cells using confocal laser scanning microscopy (CLSM). Results showed that EIP-K + H2O2 significantly reduced biofilm biomass relative to controls and that the compounds are effective at nanomolar concentrations

Ventilated Trombe wall as a passive solar heating and cooling retrofitting approach; a low-tech design for off-grid settlements in semi-arid climates

In the coming years, it is anticipated that if we continue with the same pace of energy consumption, communities will continue to face three major challenges; a mounting increase in energy demands, pollution, and global warming. On a local scale, Egypt is experiencing one of its most serious energy crises in decades. The energy consumed in indoor cooling and heating is the biggest portion of total energy consumption in residential buildings. This paper is an experimental simulation study for building retrofitting in off-grid settlements in semi-arid climates, using Trombe wall as a low-tech passive heating and cooling solution. In this study, we made developments to the conventional classic Trombe wall using occupant-centered design and living lab experimental methods. The thermal efficiency of the proposed Trombe wall design is simulated during winter and summer peaks. In the proposed design we used gray paint instead of typical black paint in addition to 15 cm reversible natural wool insulation and two 3 mm thick roll-up wool curtains. The new design reduced the heating load by 94% and reduced the cooling load by 73% compared to the base case with an annual energy savings of 53,631 kWh and a reduction in CO2 emissions of 144,267 kg of CO2. The living lab test proved that the proposed design of the Trombe wall is economically viable and the payback time is 7 months. It is recommended that the proposed design be monitored for a whole year to have an accurate assessment of its efficiency. A post occupancy evaluation is also needed to measure local residents’ acceptance and perceived comfort after retrofitting

High speed modified carry save adder using a structure of multiplexers

Adders are the heart of data path circuits for any processor in digital computer and signal processing systems. Growth in technology keeps supporting efficient design of binary adders for high speed applications. In this paper, a fast and area-efficient modified carry save adder (CSA) is presented. A multiplexer based design of full adder is proposed to implement the structure of the CSA. The proposed design of full adder is employed in designing all stages of traditional CSA. By modifying the design of full adder in CSA, the complexity and area of the design can be reduced, resulting in reduced delay time. The VHDL implementations of CSA adders including (the proposed version, traditional CSA, and modified CSAs presented in literature) are simulated using Quartus II synthesis software tool with the altera FPGA EP2C5T144C6 device (Cyclone II). Simulation results of 64-bit adder designs demonstrate the average improvement of 17.75%, 1.60%, and 8.81% respectively for the worst case time, thermal power dissipation and number of FPGA logic elements

3D Stereo Rendering Using FPGA

Stereo rendering presents a virtual 3D scene from two slightly different vantage points. It is of great importance in the field of machine vision, robotics and image analysis. This paper proposes a stereo vision system that is realized in a single field programmable gate array (FPGA). Calculations of the stereo pairs are made by using  two-center projection (off-axis) method. The first red resultant image is for left eye while the second blue one is for right eye; the 3D illusion is produced when looking to them using anaglyph. This computer graphic hardware system is implemented using Spartan3E XC3S500E FPGA kit. The execution time for the proposal is 1266 faster than OpenGL time with maximum operating frequency of 35.417 MHz, while the max occupation area reaches 84%. Keywords: Computer Graphic; Stereoscopic; anaglyph; FPGA; two-center projection ;Off-axis Method; stereo pairs. DOI: 10.7176/CEIS/10-3-04 Publication date: April 30th 201

WHAT DO COMMUNITY HEALTH WORKERS NEED TO PROVIDE COMPREHENSIVE CARE THAT INCORPORATES NON-COMMUNICABLE DISEASES?

Non-Communicable Diseases (NCDs) such as heart disease, stroke, cancer, chronic respiratory diseases and diabetes are the leading cause of premature death and disability worldwide, accounting for 60% of all deaths globally and 80% of NCD related mortality occurring in low and middle-income countries (LMICs). Health systems in LMICs have been oriented toward maternal and child health, and infectious illnesses as these were the main causes of morbidity and mortality until recently. Over the last decade, health systems in LMICs have recognized the need to address NCDs, and have restructured health services to include relevant prevention and control strategies. Health workforce is one of the key building blocks of health systems; however, most LMICs have a shortage of physicians. In addition, the available health care providers are unevenly distributed within countries with the majority concentrated in urban regions compared to rural regions where large proportions of the population reside. This poor distribution and shortage of physicians has led some countries to rely on task shifting, where tasks normally performed by qualified health professionals are transferred to other health providers with a lower level of education and professional training. In 1978, the Declaration of Alma-Ata included trained community health workers (CHWs) and traditional medical practitioners as part of the health team as a fundamental step towards comprehensive primary care. Since then, CHWs have been a cornerstone of health systems in several countries with over 26 different CHW programs identified in the literature across more than 24 LMICs. Traditionally, CHWs do not hold formal professional certification but receive job-related pre-service training. However, there is a lot of variation across countries where some countries require CHW certification before they can start performing their roles. CHWs reside in the community where they work, and are usually volunteers and sometimes receive financial compensation for receiving training and performance-based incentives for health related activities. CHWs can enable essential health care services to be provided in a cost-effective manner. They have been instrumental in reducing maternal and neonatal mortality rates through their presence for home births and making referrals for emergency obstetric care, and by promoting vaccination uptake, breastfeeding, and education about infectious disease. More recently, CHWs have been useful in HIV/AIDS prevention and control, educating communities and performing tasks such as screening, counselling and supplying antiretroviral drugs. With the increasing prevalence of NCDs and to meet changing community health needs, CHWs are sought to provide a similarly appropriate care for NCD risk factors control. While CHWs may not replace qualified health providers, they can play a considerable role in improving health outcomes by educating, screening, referring and following-up individuals at high risk of NCDs. CHWs have been trained in some settings to screen, educate and follow-up patients with NCDs or people at increased risk of NCDs. However, there is a need to better understand how to support CHW programs to be more effective and sustainable. There is knowledge gap in terms of the CHWs current capacity, working conditions, training provided for NCD prevention and control, remuneration, supervision and other upstream challenges facing CHWs and the health systems. The literature suggests that the there is a range of context-specific factors which can have an impact on the performance of CHWs and the quality of the care they provide. Some of these factors include the remuneration schemes employed, the workload, task complexity, lack of clarity in job description, and other essential factors such as interpersonal relationships between CHWs and other members of the primary health care team. CHW programs operate differently across and within countries. Evidence-based policy interventions are required to inform policy decision to ensure effective CHW program implementation. This thesis applies a mixed-methods approach to explore the capacity of the CHWs and the system support necessary to facilitate the CHW’s role in providing comprehensive, community-oriented, continuous primary health care which includes prevention and control strategies for NCDs. Part One provides an insight into the historical background of CHWs and how their role has evolved due to global health needs. With the expanding role of CHWs to incorporate NCDs, part two throws light on training of CHWs for NCDs in LMICs. Chapter two presents results of a systematic review about the effectiveness of training CHWs for cardiovascular disease prevention and management in LMICs. The chapter findings demonstrate the importance of having interactive and culturally adapted training sessions to make the training easier to follow and understand by the CHWs. The findings also highlight the need for evaluating the knowledge and skill-set of the CHWs to capture the training impact; and the necessity of scheduling refresher training at regular intervals to ensure knowledge retention. Chapter three demonstrates the importance of using an evaluation framework such as Kirkpatrick’s evaluation model to evaluate the effectiveness of training among CHWs. Using an evaluation framework, not only assesses the knowledge change but rather employs multiple measures to assess knowledge, skills and behaviour change of the CHWs. This allows for a more comprehensive interpretation of the training outcomes. The qualitative data involved in Chapter three provided insight on the low morale and discontent of the CHWs with their working conditions. In part three, I use a discrete choice experiment (DCE) to provide evidence of effective interventions that can keep the CHWs motivated and retain them in the workforce. Chapter Four explains the process of designing a DCE for Accredited Social Health Activists (ASHAs), who are CHWs in India. It also provides evidence of the feasibility of using Android computer tablets to display the DCE for the CHWs. In chapter five, I examine the relative importance of stated preferences of ASHAs to remain in service using a DCE survey. Career progression was found to be the main influencing factor for ASHAs in addition to fixed salary and other non-financial factors such as priority free family health-check and reduced workload. The findings demonstrated that the ASHAs sociodemographic characteristics such as their education level plays a key role in shaping their preference profile. These findings can inform future policy decisions of evidence-based recruitment and retention strategies that are applicable to the local context. CHWs have proven to be effective in providing a wide range of services including NCDs care. However to optimize the performance of CHW programs, we need to understand the system level support needed and the strategies necessary to be considered in the design and operation of CHWs’ programs. Part four, investigates the policy and implementation elements and system level support needed to enable the CHWs in rural India to provide comprehensive primary health care that incorporates NCDs. Chapter six uses policy review and qualitative research to understand the policy and implementation gaps, current capacity, working conditions and challenges faced by ASHAs in providing NCDs care to their community. It provides an overview of the perspectives of the key stakeholders of the ASHA program including ASHAs, ANMs, primary care doctors, community members, and district medical officers. Findings revealed that ASHAs are unrecognised as formal members of the NCDs delivery team, however they are overburdened with extensive NCDs tasks without receiving training or remuneration for these tasks. ASHAs remain to be volunteers that receive performance based remuneration and are not covered by any of the workers’ rights or laws. However, ASHAs remain enthusiastic about helping their communities and aspire to be recognised as formal employees of the health system with a potential career progression pathway. The concluding chapter summarises the key findings, discusses the main themes emerging from the thesis and outlines the future research directions and policy recommendations