A Systematic Framework for Quantifying Production System-Specific Challenges in Life Cycle Inventory Data Collection

Understanding the environmental impacts of production setups and process parameters is a necessity for process optimization and new process development within sustainable manufacturing. Previous research studies have focused on developing standard methodologies and frameworks for parametrically modelling the life cycle inventories of unit manufacturing processes. However, these approaches do not fully account for the challenges associated with implementing life cycle inventory models in real-world production setups. Therefore, the time- and cost-intensiveness associated with constructing such models limit their use for identifying sustainability-focused process improvements in complex, real-world production processes. To address the above challenges, this paper proposes a framework to identify process inventory data that have a significant influence on process resource consumption, taking into consideration the difficulties and variabilities in measuring these data. The overarching goal is to identify feasible process improvements from the perspective of process monitoring for sustainable manufacturing. The application of the proposed framework is presented using a case study on a real-world through-feed centerless grinding production process for rotor manufacturing. This study reveals grinding time is the most sensitive process parameter among the other time-related parameters. The manual nature of the process, lack of a data acquisition system, non-standardized sequence of operation, and inability to capture in-process measurements without disrupting real-time production significantly contributes to the difficulty and variability of measuring grinding time

Rub-impact analysis in rotor dynamic systems

Considering the needs of high rotating speed and high efficiency in the modern machines, the decreasing clearance between the rotor and the stator is a necessary design. To improve the performance efficiency of these kinds of machines, the radial clearance between the rotating rotor and the stator becomes smaller and smaller. As a result, it is easier for rotor-stator rub to happen and the normal operation of machines will be affected more severely. When a rub-impact happens, the partial rub arises at first. During a complete period, the rub and impact interactions occur between the rotor and stator once or fewer times. Gradual deterioration of the partial rub will lead to the full rub and then the vibration will affect the normal operation of the machines severely. The majority of works was focused on the development of some mathematical models in order to make the rubbing phenomenon more accurately to be understood in the past few decades. Now in our work general model of a rub-impact rotor-bearing system is set up and the corresponding governing motion equations are given. The rubbing model consists of the following forces i.e., radial elastic impact and the tangential Coulomb type of friction. Through numerical calculations, rotating speeds, unbalance and stiffness values are used as control parameters to investigate their effect on the rotor-dynamic system with the help of time histories, phase plane plots, whirl orbits. Complicated motions, such as periodic, quasi-periodic even chaotic vibrations, are observed under different operating conditions. Stator flexibility effects are also studied using a modified Jeffcott rotor model .Numerical methods employed in our work are Newmark’s method and Runge-Kutta method .The Graphs that have been obtained from both methods were compared Finite Element Model of the rotor dynamic system is developed with 2-noded Timoshenko beam elements. The rotary degrees of freedom are eliminated by static condensation. The Campbell diagram is obtained by accounting both gyroscopic effect and Viscous damping matrices. The Newmark time integration scheme is adopted again by incorporating the intermittent rubbing forces at the central node simulating the rigid disk stator interactions and we are trying to get the results, to compare with the obtained results. The thesis is organized as follows: Chapter-1 describes introduction to rotor dynamic problem and literature survey. Chapter-2 deals with the dynamic modeling and equations of motion of various models considered in the present work. Chapter-3 describes the results part as solution of these equations. Chapter-4 gives summary and conclusions of the work

Recovery of Xanthan Gum from Palm Oil-Based Fermentation Broth by Diafiltration with Flat Polysulfone Microfiltration (MF) Membrane

Xanthan gum recovery from palm oil-based broth by diafiltration was carried out using flat microfiltration (MF) membrane. Optimization of process parameters such as transmembrane pressure (TMP), crossflow velocity (CFV), ionic strength (IS) and diafiltration factor (DF) was performed by Taguchi method using signal-to-noise (S/N) ratio of larger-the-better criterion yielding the following optimum conditions: level 1, level 2, level 3, and level 2, respectively, corresponding to Xanthan recovery of 68 %. Analysis of variance (ANOVA) showed the significance of TMP on providing a driving force for Xanthan’s transmembrane transport (XTT), whereas little effect of DF indicated the evidence of sieving action by cake layer on XTT, which was also responsible for complete rejection of oil indicated by the absence of fatty acid component in permeate upon GC-MS analysis. On the contrary, better XTT was observed during MF operation on zero-oil broth due to absence of oily cake layer rendering CFV more effective

Real-Time Target Sound Extraction

We present the first neural network model to achieve real-time and streaming target sound extraction. To accomplish this, we propose Waveformer, an encoder-decoder architecture with a stack of dilated causal convolution layers as the encoder, and a transformer decoder layer as the decoder. This hybrid architecture uses dilated causal convolutions for processing large receptive fields in a computationally efficient manner while also leveraging the generalization performance of transformer-based architectures. Our evaluations show as much as 2.2-3.3 dB improvement in SI-SNRi compared to the prior models for this task while having a 1.2-4x smaller model size and a 1.5-2x lower runtime. We provide code, dataset, and audio samples: https://waveformer.cs.washington.edu/.Comment: ICASSP 2023 camera-read

Effectiveness of CFD simulation for the performance prediction of phase change building boards in the thermal environment control of indoor spaces

This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2013 ElsevierThis paper reports on a validation study of CFD models used to predict the effect of PCM clay boards on the control of indoor environments, in ventilated and non-ventilated situations. Unlike multi-zonal models, CFD is important in situations where localised properties are essential such as in buildings with complex and large geometries. The employed phase change model considers temperature/enthalpy hysteresis and varying enthalpy-temperature characteristics to more accurately simulate the phase change behaviour of the PCM boards compared to the standard default modelling approach in the commercial CFD codes. Successful validation was obtained with a mean error of 1.0 K relative to experimental data, and the results show that in addition to providing satisfactory quantitative results, CFD also provides qualitative results which are useful in the effective design of indoor thermal environment control systems utilising PCM. These results include: i) temperature and air flow distribution within the space resulting from the use of PCM boards and different night ventilation rates; ii) the fraction of PCM experiencing phase change and is effective in the control of the indoor thermal environment, enabling optimisation of the location of the boards; and iii) the energy impact of PCM boards and adequate ventilation configurations for effective night charging.This work was funded through sponsorship from the UK Engineering and Physical Sciences Research Council (EPSRC), Grant No: EP/H004181/1

Xanthan GumRecovery from Palm Oil-Based Fermentation Broth by Hollow Fibre Microfiltration (MF) Membrane with ProcessOptimisation Using Taguchi Method

First stage Xanthan recovery (cell and oil separation) from palm oil-based fermentation broth was carried out by hollow fibre microfiltration (MF) using Taguchi method as design of experiment (DOE) to study the effect of four main parameters on Xanthan recovery; transmembrane pressure (TMP), crossflow velocity (CFV), ionic strength (IS) and temperature (T). From S/N ratio larger-the-better analysis, optimum conditions for Xanthan recovery were at level 2 of TMP, IS and T respectively and level 1 for CFV whereas the significance of factor found by ANOVA was in the following order: IS > TMP > T > CFV. Confirmation experiment based on optimum condition yield 64 % Xanthan recovery. Particle size was influenced by intramolecular and intermolecular interactions of Xanthan’s side chain under varying pH and cation concentration and affected the degree of Xanthan’s transmembrane transport (XTT). Interpretation of zeta potential (ZP) elucidated XTT mechanism driven by surface charge modification of membrane surface due to cation binding. The formation of oily cake layer hindered most XTT, whereas better XTT achieved for zero-oil broth filtration

Coupled TRNSYS-CFD simulations evaluating the performance of PCM plate heat exchangers in an Airport Terminal building displacement conditioning system

This is the post-print version of the Article. The official published version can be accessed from the link below. Copyright @ 2013 Elsevier.This paper reports on the energy performance evaluation of a displacement ventilation (DV) system in an airport departure hall, with a conventional DV diffuser and a diffuser retrofitted with a phase change material storage heat exchanger (PCM-HX). A TRNSYS-CFD quasi-dynamic coupled simulation method was employed for the analysis, whereby TRNSYS® simulates the HVAC and PID control system and ANSYS FLUENT® is used to simulate the airflow inside the airport terminal space. The PCM-HX is also simulated in CFD, and is integrated into the overall model as a secondary coupled component in the TRNSYS interface. Different night charging strategies of the PCM-HX were investigated and compared with the conventional DV diffuser. The results show that: i) the displacement ventilation system is more efficient for cooling than heating a space; ii) the addition of a PCM-HX system reduces the heating energy requirements during the intermediate and summer periods for specific night charging strategies, whereas winter heating energy remains unaffected; iii) the PCM-HX reduces cooling energy requirements, and; iv) maximum energy savings of 34% are possible with the deployment of PCM-HX retrofitted DV diffuser.This work was funded by the UK Engineering and Physical Sciences Research Council (EPSRC), Grant No: EP/H004181/1