Development of an ultrasonic resonator for ballast water disinfection

Ultrasonic disinfection involves the application of low-frequency acoustic energy in a water body to induce cavitation. The implosion of cavitation bubbles generates high speed microjets >1 km/s, intense shock wave >1 GPa, localized hot spots >1000 K, and free-radicals, resulting in cell rupture and death of micro-organisms and pathogens. Treatment of marine ballast water using power ultrasonic is an energy-intensive process. Compared with other physical treatment methods such as ultraviolet disinfection, ultrasonic disinfection require 2 to 3 orders of magnitude more energy to achieve similar rate of micro-organism mortality. Current technology limits the amount of acoustic energy that can be transferred per unit volume of fluid and presents challenges when it comes to high-flow applications. Significant advancements in ultrasonic processing technology are needed before ultrasound can be recognized as a viable alternative disinfection method. The ultrasonic resonator has been identified as one of the areas of improvement that can potentially contribute to the overall performance of an ultrasonic disinfection system. The present study focuses on the design of multiple-orifice resonators (MOR) for generating a well-distributed cavitation field. Results show that the MOR resonator offers significantly larger vibrational surface area to mass ratio. In addition, acoustic pressure measurements indicate that the MOR resonators are able of distributing the acoustic energy across a larger surface area, while generating 2-4 times higher pressures than existing ultrasonic probes

Sustainability of Cellulosic Fibres, and their Production Systems and Technologies

The textile industry will face the next biggest challenge after the industrial revolution when the raw materials of the synthetics (non-renewable petrochemicals) start to run off. Considering the fact that about 60.6% of the fibres consumed in 2009 are produced from petrochemical sources, it is clear that a high dependence of the textile industry on crude is very concrete. Cotton, the second largest consumed fibre with around 32% share in the global fibre consumption in 2009, doesn't have a promising future scope for growth. Some of the reasons are its productivity already being affected due to climate change, larger land demand for food and biofuels production, and also land needs for growing population around the world. A solution in the foreseeable future can only be possible with manufactured fibres made from renewable resources like cellulose. This work is an investigation on the sustainability of the cellulosic fibres' (including cotton) production systems and technologies. The investigation is carried by applying the UN’s working list of indicators of sustainable development on the member countries of the United Nations segmented into country blocks in this work. A scoring method has been introduced to quantify the sustainability indicators. The sustainability of viscose and lyocell production systems along with that of cotton and polyester in different coun-try blocks were quantified using the index and compared. It has been found that Block 1 countries (the developed nations of the world) and Block 2 countries (highly populated and developing nations of the world), as explained in this work, have respectively the most conducive conditions and least conducive conditions to run any fibre production system sustainably. Lyocell is more sustainable than viscose anywhere in the world. However, the sustainability of any cellulosic fibre production system, including Lyocell, can substantially be increased by using wood pulps also from temperate forests. Out of the four fibre production systems cotton seems to be most un-sustainable, and polyester seems to be the most sustainable. /Kir1

Hopf Bifurcation and Stability of Periodic Solutions for Delay Differential Model of HIV Infection of CD4 +

This paper deals with stability and Hopf bifurcation analyses of a mathematical model of HIV infection of CD4+ T-cells. The model is based on a system of delay differential equations with logistic growth term and antiretroviral treatment with a discrete time delay, which plays a main role in changing the stability of each steady state. By fixing the time delay as a bifurcation parameter, we get a limit cycle bifurcation about the infected steady state. We study the effect of the time delay on the stability of the endemically infected equilibrium. We derive explicit formulae to determine the stability and direction of the limit cycles by using center manifold theory and normal form method. Numerical simulations are presented to illustrate the results

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Simulation studies for multichannel active vibration control

Traditional approach to vibration control uses passive techniques, which are relatively large, costly and ineffective at low frequencies. Active Vibration Control (AVC) is used to overcome these problems and in AVC additional sources (secondary) are used to cancel vibration from primary source based on the principle of superposition theorem Since the characteristics of the vibration source and environment are time varying, the AVC system must be adaptive. Adaptive systems have the ability to track time varying disturbances and provide optimal control over a much broader range of conditions than conventional fixed control systems. In multi channel AVC vibration fields in large dimensions are controlled and is more complicated. Therefore to actively control low frequency vibrations on large structures, multi channel AVC requires a control system that uses multiple secondary sources to control the vibration field simultaneously at multiple error sensor locations. The error criterion that can be directly measured is the sum of squares of outputs of number of sensors. The adaptive algorithm is designed to minimize this and the algorithm implemented is the quot;Multiple error LMS algorithmquot;. The best known applications of multiple channel FXLMS algorithm is in real time AVC and system identification. Additionalr applications are in the control of propeller induced noise in flight cabin interiors. In the present paper the results of simulation studies carried out in MATLAB as well as on TMS320C32 DSP processor will be brought out for a two-channel case

Ground Resonance Test and Response analysis of HS 748 aircraft a Preliminary report

The report deals with the preliminary results obtainer from the ground resonance test and response analysis of I1S 74" Aircraft. Comparisons of wing natural frequencies obtained from different excitations have: been made. Modal analysis results the wing are also enclosed . Recommendation for further tests the present and modified configurations of the aircraft have been include

Sustainability of Cellulosic Fibres, and their Production Systems and Technologies

The textile industry will face the next biggest challenge after the industrial revolution when the raw materials of the synthetics (non-renewable petrochemicals) start to run off. Considering the fact that about 60.6% of the fibres consumed in 2009 are produced from petrochemical sources, it is clear that a high dependence of the textile industry on crude is very concrete. Cotton, the second largest consumed fibre with around 32% share in the global fibre consumption in 2009, doesn't have a promising future scope for growth. Some of the reasons are its productivity already being affected due to climate change, larger land demand for food and biofuels production, and also land needs for growing population around the world. A solution in the foreseeable future can only be possible with manufactured fibres made from renewable resources like cellulose. This work is an investigation on the sustainability of the cellulosic fibres' (including cotton) production systems and technologies. The investigation is carried by applying the UN’s working list of indicators of sustainable development on the member countries of the United Nations segmented into country blocks in this work. A scoring method has been introduced to quantify the sustainability indicators. The sustainability of viscose and lyocell production systems along with that of cotton and polyester in different coun-try blocks were quantified using the index and compared. It has been found that Block 1 countries (the developed nations of the world) and Block 2 countries (highly populated and developing nations of the world), as explained in this work, have respectively the most conducive conditions and least conducive conditions to run any fibre production system sustainably. Lyocell is more sustainable than viscose anywhere in the world. However, the sustainability of any cellulosic fibre production system, including Lyocell, can substantially be increased by using wood pulps also from temperate forests. Out of the four fibre production systems cotton seems to be most un-sustainable, and polyester seems to be the most sustainable. /Kir1

Synchronization of Markovian jumping inertial neural networks and its applications in image encryption

This study is mainly concerned with the problem on synchronization criteria for Markovian jumping time delayed bidirectional associative memory neural networks and their applications in secure image communications. Based on the variable transformation method, the addressed second order differential equations are transformed into first order differential equations. Then, by constructing a suitable Lyapunov–Krasovskii functional and based on integral inequalities, the criteria which ensure the synchronization between the uncontrolled system and controlled system are established through designed feedback controllers and linear matrix inequalities. Further, the proposed results proved that the error system is globally asymptotically stable in the mean square. Moreover, numerical illustrations are provided to validate the effectiveness of the derived analytical results. Finally, the application of addressed system is explored via image encryption/decryption process