Replication of mixing achieved in large co-rotating screw extruder using a novel laboratory 10-100g minimixer

YesWhen compounding polymers with additives to develop materials at specifications (colouring plastics is the simplest example), the difficulties is in getting the formulation right the first time. Also, when developing completely new materials such as in nanotechnology applications, there is a need to do the initial trials safely and with as small quantities as possible to enable a wide range of experimentation. Wiith traditional applications, often the initial compounding formulation is done using small single or twin screw extruders but with machines that have a fair output to instruct the large scale operation. This step is costly in material wastage and time but more importantly it often does not provide the right formulation which in turn results in bigger wastage cost at the industrial scale before the right formulation is eventually obtained. With the very new material formulations, any reduction in cost of development is always essential. With these aims in mind, we have developed a new minimixer capable of handling tiny quantities of order 10-100g but the minimixer is capable of reproducing the very high mixing conditions experienced in large machines. This invention provides a new opportunity to develop new products quickly, safely and cheaply. The application is not restricted to polymers and can be extended to other soft materials. It has also other spin-offs as a research tool for studying mixing and developing new, more efficient, mixing flows. In this paper we explain the principle of operation we have engineered to produce such intense mixing. Basically, the device is based on combining two opposing flows: a single screw extruder circulation flow with a twin screw extruder mixing flow. The mixing is carried out as a batch but on its completion, the single screw extruder flow is reversed and becomes co-current with the twin extruder flow to enable the discharging of the batch through a die. In the paper we present mixing data obtained with various polymer-additive combinations tested in the minimixer under various conditions of screw speeds, mixing times and temperatures and at the larger scale to underpin the operation of this novel mixer. The quality of mixing of the extrudate was measured using a variety of methods depending on applications: using image analysis of microtome sections of the extrudate or of blown film samples produced from the formulations or measuring electrical properties

Development of a Dynamic Fouling Model for a Heat Exchanger

yesFouling in heat exchangers (HE) is a major problem in industry and accurate prediction of the onset or degree of fouling would be of a huge benefit to the operators. Modelling of the fouling phenomenon however, remains a challenging field of study. Cleaning of heat exchangers, coulpled with the down time, is a financial burden and for industrialized nations and costs can reach to almost 0.25 % of the country’s Gross National Product (Pritchard, 1988).This work presents the development of a dynamic fouling model based on experimental data collected using a laboratory concentric tube heat exchanger handling a saline system. Heat transfer coefficients were obtained from first principles as well as from either the Sieder-Tate or Petukhov-Kirillov correlations modified by Gnielinski depending on the flow regime. The outlet temperatures were calculated using the Effectiveness-NTU method. The dynamic fouling factor was based on the Kern and Seaton fouling model and validation was completed by comparing the experimental outlet temperatures with those predicted by the model. The model predicts the outlet temperatures with an average discrepancy of 1.6 °C and 0.4 °C for the cold and hot streams respectively

Greening Chemical Engineering laboratory at Bradford University

YesThis paper highlights the work undertaken to assess the current state of the art of the Chemical Engineering Laboratory at the University of Bradford (UK) in terms of total energy and water usage and sound pollution and to propose an action plan to ‘greening’ the laboratory so that future students are trained in a laboratory where sustainability is the key feature of all learning activities. The project was funded by National Higher Education STEM (Science Technology Engineering and Mathematics) Programme. This review and assessment was carried out by two academic staff and one technical staff member with chemical engineering background.National HE STEM Programm

Maximization of gasoline in an industrial FCC unit

YesThe Riser of a Fluid Catalytic Cracking (FCC) unit cracks gas oil to make fuels such as gasoline and diesel. However, changes in quality, nature of crude oil blends feedstocks, environmental changes and the desire to obtain higher profitability, lead to many alternative operating conditions of the FCC riser. The production objective of the riser is usually the maximization of gasoline and diesel. Here, an optimisation framework is developed in gPROMS to maximise the gasoline in the riser of an industrial FCC unit (reported in the literature) while optimising mass flowrates of catalyst and gas oil. A detailed mathematical model of the process developed is incorporated in the optimisation framework. It was found that, concurrent use of the optimal values of mass flowrates of catalyst (310.8 kg/s) and gas oil (44.8 kg/s) gives the lowest yield of gases, but when these optimum mass flowrates are used one at time, they produced the same and better yield of gasoline (0.554 kg lump/ kg feed).Petroleum Technology Development Fund, Nigeria, financially sponsored the study

Cognitive Rehab Solutions: A computer-assisted cognitive training program

The purpose of this project is to offer a functionally comprehensive application, Cognitive Rehab Solutions (CRS), that is designed for neuropsychologists to deliver restorative cognitive training in areas of attention and memory of persons with brain impairment

Evaluation of cascaded inertial vibration isolation systems

Cascaded inertial vibration isolation systems are examined in this report. Systems employing one, two or three masses in series on isolators are investigated. The objective is to determine if the cascaded systems have appreciable advantages over the classical single mass system. The equations of motion for these systems are derived by applying Newton\u27s second law of motion. The homogeneous and steady state sinusoidal excitation solutions have been established. Transmissibility of forces and moments to the foundation has been obtained for several cases of force excitation. Comparisons of the cases investigated are based upon the principal mode frequencies, mode shapes, center of mass displacements and transmissibilities. The ratio of the maximum forcing function to the total weight of the system has in all cases been held at a level of one to four. The spring coefficients have been chosen such that each sub-system, i.e., one mass and its direct supporting springs, have a natural frequency of approximately one cps. The amplitudes of the top mass, in general, increase with the natural frequency bandwidths. Cases which do not follow this trend are those where some isolators connect the top mass directly to the foundation and cases having a lighter mass at the top. Transmissibilities are the lowest for the three mass system and the highest for the conventional one mass system --Abstract, page ii

Review Presentation of Different Economic Order Quantity (EOQ) Models and Their Application

In the context of inventory management, this review presentation offers a thorough overview of several Economic Order Quantity (EOQ) models and their real-world uses. It explores the fundamental EOQ model and broadens to incorporate models that account for perishable items, quantity discounts, and scarcity prices. The talk also looks at the many sectors in which these models are used to optimize order amounts, save costs, and improve operational efficiency. Businesses may improve their inventory control strategies, realize considerable cost savings, and increase performance by making educated decisions based on a thorough grasp of the various EOQ models and their practical implementations

Investigation of Plasma Treatment on Micro-Injection Moulded Microneedle for Drug Delivery

YesPlasma technology has been widely used to increase the surface energy of the polymer surfaces for many industrial applications; in particular to increase in wettability. The present work was carried out to investigate how surface modification using plasma treatment modifies the surface energy of micro-injection moulded microneedles and its influence on drug delivery. Microneedles of polyether ether ketone and polycarbonate and have been manufactured using micro-injection moulding and samples from each production batch have been subsequently subjected to a range of plasma treatment. These samples were coated with bovine serum albumin to study the protein adsorption on these treated polymer surfaces. Sample surfaces structures, before and after treatment, were studied using atomic force microscope and surface energies have been obtained using contact angle measurement and calculated using the Owens-Wendt theory. Adsorption performance of bovine serum albumin and release kinetics for each sample set was assessed using a Franz diffusion cell. Results indicate that plasma treatment significantly increases the surface energy and roughness of the microneedles resulting in better adsorption and release of BSA

Near Infrared Investigation of Polypropylene-Clay Nanocomposites for Further Quality Control Purposes-Opportunities and Limitations

YesPolymer nanocomposites are usually characterized using various methods, such as small angle X-ray diffraction (XRD) or transmission electron microscopy, to gain insights into the morphology of the material. The disadvantages of these common characterization methods are that they are expensive and time consuming in terms of sample preparation and testing. In this work, near infrared spectroscopy (NIR) spectroscopy is used to characterize nanocomposites produced using a unique twin-screw mini-mixer, which is able to replicate, at ~25 g scale, the same mixing quality as in larger scale twin screw extruders. We correlated the results of X-ray diffraction, transmission electron microscopy, G′ and G″ from rotational rheology, Young’s modulus, and tensile strength with those of NIR spectroscopy. Our work has demonstrated that NIR-technology is suitable for quantitative characterization of such properties. Furthermore, the results are very promising regarding the fact that the NIR probe can be installed in a nanocomposite-processing twin screw extruder to measure inline and in real time, and could be used to help optimize the compounding process for increased quality, consistency, and enhanced product propertie

Replay Attack Detection in Smart Grids using Switching Multi-sine Watermarking

Cyber-Physical Systems (CPS) are systems that include physical and computational components linked by communication channels. In a Smart Grid (SG), the power plants and loads communicate with supervisors (Central Controllers (CC)) for managing the power demand more efficiently. As such, a smart grid can be regarded as a CPS. The computational components and communication links of a CPS can be subject to cyber-attacks. Researchers have been exploring detection and mitigation strategies for various types of cyber-attacks. An important type of attack is the replay attack for which various strategies based on watermarking signals have been proposed. One such scheme is based on switching multi-sine waves as the watermarking signal. This thesis adapts this scheme and develops a design procedure for detecting replay attacks for smart grids. Specifically, it examines the places in a grid where the watermarking signal can be injected and presents guidelines for choosing the amplitude and frequencies of sine waves that suit smart grids. One of the drawbacks of using a watermarking signal is the additional control cost (i.e., decrease in performance). In the context of smart grids, watermarking results in small fluctuations in delivered power. This thesis extends the single-input-single-output watermarking to a two-input-two-output watermarking scheme for smart grids in such a way to considerably lower grid power fluctuations due to watermarking. The proposed method is verified using a simulated grid connected inverter-based plants. Simulation results show that using the suggested strategy, the effect of watermarking on the overall grid power reduces significantly