Investigating the Potential of Waste Heat Recovery as a Pathway for Heavy-Duty Exhaust Aftertreatment Thermal Management

Heavy-duty diesel (HDD) engines are the primary propulsion source for most heavy-duty vehicle freight movement and have been equipped with an array of aftertreatment devices to comply with more stringent emissions regulations. In light of concerns about the transportation sector\u27s influence on climate change, legislators are introducing requirements calling for significant reductions in fuel consumption and thereby, greenhouse gas (GHG) emission over the coming decades. Advanced engine concepts and technologies will be needed to boost engine efficiencies. However, increasing the engine\u27s efficiency may result in a reduction in thermal energy of the exhaust gas, thus contributing to lower exhaust temperature, potentially affecting after-treatment activity, and consequently emissions rate of regulated pollutants.;As an aftertreatment thermal management for selective catalytic reduction (SCR) system, this study investigates the possible utilization of waste heat recovered from a HDD engine as a means to offset fuel penalty incurred during thermal management of SCR system. Experiments were aimed at conducting detailed energy audit of a MY 2011 heavy-duty diesel engine equipped with a DPF and SCR. A MATLABRTM based steady-state simulation tool was developed to simulate a waste heat recovery system (WHRS) based on an Organic Rankine Cycle (ORC), working with three different organic fluids, and primarily harvesting energy from combinations of the engine\u27s heat dissipating circuits. The simulations were based on experimental data obtained through a comprehensive characterization of engine energy distribution using a heavy-duty engine dynamometer.;Results obtained from the ORC-WHRS simulation over the engine operating points showed that the working fluids, R123 and R245fa with utilizing post-SCR exhaust stream, and exhaust gas recirculation (EGR) cooler as the two heat sources provided the optimum performance. As the primary goal of this study was to understand the utilization of a WHRS as a strategy for thermal management of an after-treatment system in reducing NOx levels, the study further investigates into the dynamic operation of a heavy-duty diesel engine from an actual vehicle testing. Assessment on magnitude of the energy generated for the transient vehicle operation does show ORC-WHRS as a feasible application in reaching the desired thermal state of a typical HDD engine SCR system

Development of an Ammonia Reduction After-Treatment Systems for Stoichiometric Natural Gas Engines

Three-way catalyst (TWC) equipped stoichiometric natural gas vehicles have proven to be an effective alternative fuel strategy that shows significant low NOx emissions characteristics. However, recent studies have shown the TWC activity to contribute to elevated levels of tailpipe ammonia (NH 3) emissions. Although a non-regulated pollutant, ammonia is a potent pre-cursor to ambient secondary PM formation. Ammonia is an inevitable byproduct of fuel rich operation that results in lowest NOx slip through the TWC after-treatment system.;The main objective of the study is to develop a passive Ammonia Reduction Catalyst (passive-ARC) based NH3 reduction strategy that results in an overall reduction of ammonia as well as NOx emissions. The study investigated the characteristics of Fe-based and Cu-based zeolites SCR catalysts in storage and desorption of ammonia at high exhaust temperature conditions, that are typical of stoichiometric natural gas engines. Continuous measurements of NOx and NH3 before and after the SCR systems were conducted using a Fourier Transform Infrared Spectrometry (FTIR) gas analyzer. Results of the investigation showed that both, the Fe- and Cu zeolite SCRs adsorbed above 90% of TWC generated NH3 emissions below 350--375 °C SCR temperatures. Desorption or slipping of NH3 was observed at exhaust gas temperatures exceeding 400 °C. In terms of NOx conversions, Fe-zeolite showed efficiency between 50--80% above temperatures of 300--350 °C while Cu-zeolite performed well at lower SCR temperature from 250 °C and above with a conversion efficiency of greater than 50%.;In order to efficiently reduce both NOx and NH3 simultaneously over longer durations it was found that an engine-based air fuel ratio operation strategy for the passive-ARC system must be developed. To this extent, the study extended its objectives to develop an engine-based control strategy that results in stoichiometric ammonia production operation followed by brief lean operation to regenerate the saturated ammonia reduction catalyst using high NOx slip through TWC. The study presents comprehensive results of ammonia storage characteristics of SCRs pertaining to stoichiometric natural gas engine exhaust as well as an advanced engine control strategy approach to simultaneously reduce both NOx and NH3 using an alternating air -fuel ratio approach

Navigation Techniques for Control of Multiple Mobile Robots

The investigation reported in this thesis attempt to develop efficient techniques for the control of multiple mobile robots in an unknown environment. Mobile robots are key components in industrial automation, service provision, and unmanned space exploration. This thesis addresses eight different techniques for the navigation of multiple mobile robots. These are fuzzy logic, neural network, neuro-fuzzy, rule-base, rule-based-neuro-fuzzy, potential field, potential-field-neuro-fuzzy, and simulated-annealing- potential-field- neuro-fuzzy techniques. The main components of this thesis comprises of eight chapters. Following the literature survey in Chapter-2, Chapter-3 describes how to calculate the heading angle for the mobile robots in terms of left wheel velocity and right wheel velocity of the robot. In Chapter-4 a fuzzy logic technique has been analysed. The fuzzy logic technique uses different membership functions for navigation of the multiple mobile robots, which can perform obs..

Dynamics in a Respiratory Control Model With Two Delays

In this paper we study ventilation patterns in a set of parameter dependent nonlinear delay equations with two transport delays modeling the human respiratory control system with peripheral and central control loops. We present a convergent numerical scheme suitable to perform simulations when all disturbances and system parameters are known, then we consider the numerical identifiability of various system parameters based on ventilation data. We are especially interested in the identification of the transport delays in the control loops because these parameters are not measurable directly, but they have a strong influence on system stability/instability

COMPARATIVE ANALYSIS OF MORPHOLOGY AND PHYTOCHEMICAL CONSTITUENTS IN DIFFERENT POPULATIONS AND MORPHOTYPES OF DATURA INNOXIA MILL. AND DATURA METEL L. FROM PUNJAB PLAINS

Objective: Comparative analysis of morphology and phytochemical constituents in different populations and morphotypes of Datura innoxia Mill. and Datura metel L. from Punjab plains.Methods: Morphological analyses of different populations have been done. Methanol extracts of seeds and roots of different populations have been prepared and total phenols, flavonoid contents were measured through spectrophotometry. Antioxidant activity was studied by 2, 2-diphenyl-1- picrylhydrazyl radical scavenging activity and total antioxidant capacity. Two major compounds, caffeic acid and chlorogenic acid were quantified by high-performance thin-layer chromatography (HPTLC) analyses.Results: Two morphotypes of D. metel were reported in the present study. Out of five different populations of D. metel and D. innoxia, the wild populations have more bioactive compound as compared to the cultivated ones from the detailed phytochemical investigation. Pharmacologically important two marker compounds chlorogenic acid and caffeic acid has been identified and quantified by HPTLC technique.Conclusion: Variation in terms of morphology and secondary metabolites exists among the different populations of Datura spp. Among the two plant parts studied, seeds have the maximum amount of bioactive metabolites and antioxidant activity. This study revealed that chlorogenic acid and caffeic acid are the potential polyphenolic compounds in Datura spp. It has been found that the antioxidant activity of plant is due to its polyphenol contents, which provides insight to various researchers to work on it as it imparts health benefit

ELEMENTAL ANALYSIS AND BIOLOGICAL STUDIES OF PHYSALIS ANGULATA L. USING WAVE LENGTH-DISPERSIVE X-RAY FLUORESCENCE TECHNIQUE, WAVELENGTH DISPERSION X-RAY FLUORESCENCE, FROM RAJASTHAN

Physalis angulata L. is an important medicinal plant, commonly known by different names such as mullaca, wintercherry, camapu, cutleaf, andreferred as pilu,†by local tribal people of Rajasthan. This plant species is distributed from temperate to tropical region of the world. Traditionally, ithas anticancerous, antimycobacterial, and anticoagulant properties. The juice is used in the treatment of earache, jaundice, fever, gonorrhea bladderdiseases, etc., cytological exploration of the species from Rajasthan revels the existence of two cytotypes diploid (2n=12) and tetraploid (2n=24). Thisstudy is undertaken to identify the total mineral content of both the cytotypes from different plant parts, i.e., fruit, leaf, stem, and roots by wavelength dispersion X-ray fluorescence technique which is a simple method, recognized as a nondestructive technique to determine the elements from the raw plant material without any chemical treatment and helps to ascertain the nutritional role. The analysis of mineral content led to the identification and concentration analysis of twenty-seven elements in diploid cytotype and twenty-five in tetraploid cytotype. The percentage value of potassium (5.52%); iron (0.50%) and selenium (0.0042%) is reported to be higher in diploid cytotype and the amount of calcium (2.15%); magnesium (0.75%) and zinc (0.0075%) are higher in tetraploid cytotype. The amount of most of the minerals is higher in tetraploid cytotype as compared to the diploid cytotype. This information is very helpful in standardization of herbal products as this plant species is widely used for its medicinal benefits

Data issues in analyzing agri-food trade in BIMSTEC: Challenges and recommendations

The focus of research on international trade has recently shifted from industries and countries to firms. Firm heterogeneity is shown to be a determinant of trade at both the intensive margin (increase exports per firm/product) and extensive margins (the number of firms exporting – new products, new partners, new varieties, and new prices). It is now widely accepted that exporting firms are larger, comparatively productive, more skilled, and capital-intensive, and pay higher wages than non-exporting firms. The innovations in international trade literature that explains both the emergence as well as levels and the nature of trade flows through value chain integration necessitates examining trade-based exchanges at the highest possible levels of product disaggregation. Developments in trade theory emphasize that it is individual firms not countries that trade and analysis needs to incorporate firm characteristics in decisions and ability for exporting and importing. Firms are the appropriate unit of analysis for trade flows. It helps several paradoxes once the import of firm heterogeneity is understood. Despite the substantive importance of granular level data and the significant level of disaggregated product-level bilateral trade flow data and enhanced computing power that are becoming available, most studies have tended to rely on analysis with high level of aggregation. Recent research on firm heterogeneity in international trade highlights the importance of extensive margins i.e., new products, new partners, new varieties, and cumulative of these i.e., new prices in trade patterns and firms' responses to trade liberalization and other policy changes. However, the high dimensionality of the data and the large number of responses to changes can easily overwhelm researchers. Additionally, bigger data sets may contain more noise, which can mask important systematic patterns. In analysis of trade flows, notwithstanding the rising incidence of differentiated products (varieties) and value chains that transcend national boundaries, methods in agri-food trade analysis in particular have not kept pace in terms of empirical methods and suitable data

Finite Element Based Vibration Analysis of a Nonprismatic Timoshenko Beam with Transverse Open Crack

AbstractThe present day structures and machineries are designed based on optimizing of multi-objectives such as maximum strength, maximum life, minimum weight and minimum cost. Due to this they are flexible and allow having a very high level of stresses. This leads to development of cracks in their elements. Many engineering structures may have structural defects such as cracks due to long-term service. So it is very much essential to know the property of structures and its response in various cases. The present article deals with finite element based vibration analysis of a nonprismatic cracked beam. The beam is modeled using the Timoshenko beam theory. The governing equation of motion is derived by the Hamilton's principle. In order to solve the governing equation two noded beam element with two degrees of freedom (DOF) per node is considered. In this work the effect of structural damping is also incorporated in the finite element model. The dynamic analysis is carried out by using state space model in time domain

Outcome of gastrointestinal surgery during COVID-19 lockdown in a tertiary care hospital, Nepal

Introduction: Perioperative strategies have been changing due to the COVID-19 pandemic to prevent the risk of postoperative complications and transmission of infection. This study was aimed to assess the outcome of gastrointestinal surgery and the risk of transmission by implementing COVID-19 testing criteria and surgical strategy. Method: This was a retrospective descriptive study conducted at the department of surgery at Patan Hospital, Nepal, during COVID-19 lock-down from 24 march to 15 June 2020. All patients who underwent gastrointestinal (GI) surgery were included. High-risk patients (as defined by the Hospital Incident Command System, HICS) were tested for COVID-19 preoperatively. Surgery was performed in COVID operating room with full protective gear. Low-risk patients were not tested for COVID-19 preoperatively and performed surgery in non-COVID OR. Data from patient’s case-sheets were analyzed descriptively for age, gender, comorbidities, hospital stay, RT-PCR results, surgeries, and postoperative complications. Result: There were total 44 GI surgeries performed; 31(70.5%) were emergency, 5(11.3%) semi-emergency and 8(18.2%) oncology. There were 11(25%) patients tested for COVID-19 preoperatively and were negative. Nine HCWs tested for COVID-19 randomly were negative. Severe postoperative complications developed in 3 patients, with one mortality. Conclusion: Among GI surgeries, there was no increase in postoperative complications and transmission of COVID-19 to the patients or HCWs following the implementation of standard testing criteria and surgical strategy