Aging of Lean NOX Trap Catalysts and Hydrocarbon Trapping in Cold-Start Applications

It is well known that combustion processes worldwide give rise to emissions such as nitrogen oxides (NOX), carbon monoxide (CO), hydrocarbons (HC) and particulates. For vehicles, the method for handling these emissions has been through the development of the catalytic converter. For the diesel engine, the Lean NOX Trap (LNT) has been used since the 90s and is designed to function well in the high air/fuel ratio in which the diesel engine operates. The LNT often consist of a storage compound, e.g. barium, where NOX is stored in lean conditions (high air/fuel ratio). During short rich pulses (low air/fuel ratio) the NOX is released and reduced over the noble metal sites. Over time in use, these catalytic converters are exposed to the conditions that may reduce the catalytic properties of the catalyst and deactivation studies are therefore critical. Gasoline vehicles are often equipped with a hydrocarbon trap, to store HCs from the engine during the cold-start. The aim is that at higher temperature, when the catalyst is functioning, the HCs desorb and are oxidized. Chemical poisoning of an LNT catalyst, i.e. Pt/Ba/Al2O3, was studied thoroughly. Both deactivation by phosphorus (P) as well as by zinc (Zn) was examined, because these elements can be found in the lubricant oil. The catalysts were exposed to P in two different ways. In the first study, P was introduced through gas-phase exposure by evaporating phosphoric acid. In the second study, both P and Zn were introduced to the Pt/Ba/Al2O3 catalyst through wet impregnation. The main findings were that gas-phase exposure results in an axial distribution where P can exist in different oxidation states at different positions over the washcoat. Moreover, it could be seen that Zn may help to suppress the deactivation caused by P on the LNT catalyst, and the suggested reason is due to formation of zinc phosphates. Furthermore, the main cause for deactivation of the LNT catalyst by P is attributed to the interaction between P and Ba. The effect of catalyst composition was examined for HC Traps. The effect of promoting zeolites, by the addition of Pd, La and Fe, was studied. The addition of Fe did not show any significant effect on the toluene storage and release in comparison to zeolite beta. However, both Pd and La exhibited positive effects. The addition of La resulted in both an increase in the storage of toluene and an increase in the desorption temperature for toluene in wet conditions, which is beneficial. However, at higher La loadings, no beneficial effect of La could be seen. Lastly, during mixed-HC temperature programmed desorption experiments, an interaction mechanism between propane and toluene could be observed which resulted in higher adsorption capacity of propane on zeolite ZSM-5

The Retreat from the Ambiguities of Entrepreneurship: A study of Business Incubators

Title: The retreat from the ambiguities of entrepreneurship: A study of Business Incubators Submission date: May 22th 2013 Course: BUSN49 Degree Project in Managing People Knowledge and Change- Master Level Authors: Rasmus Jonsson & Emilia Olandersson Supervisor: Kate Sullivan, Department of Business Administration, School of Economics and Management, Lund University & Stefan Sveningsson, Department of Business Administration, School of Economics and Management, Lund University. Purpose: Our purpose is to gain a greater understanding of business incubators, through addressing the missing focus on tenants‘ experiences of business incubators. Methodology: The research is based on an interview study of a business incubator located, in the south of Sweden. The research was conducted from an interpretative perspective, but during the process we also took on a critical stance. Research Question: How do tenants experience being part of a business incubator? Findings: The tenants at the studied business incubator experienced the resources provided by the business incubator as having an ambiguity reducing effect, through structure and submission. Moreover, due to the business incubator promotion of a certain way of being, the tenants may have put more of their real-self into the entrepreneurial process and thus contributing to a self-disciplining effect. Originality/value: The study adds nuances to existing theories and contributes with insights for practitioners regarding how to create business incubators that better fits the needs of the tenants. By applying an interpretative and critical perspective we also put the tenants‘ experiences in center. Keywords: Business Incubators, Entrepreneurs, Resources, Structure and Ambiguity

Systems Engineering Solution

The development and realisation of urban infrastructural projects such as bridges is getting increasingly more difficult and complex to manage. The challenge for the actors to develop an effective solution for the project within the traditional dimensions of time, budget and quality is still very present. But society also calls for more sustainable solutions which minimizes an eventual negative impact on the environment and takes into account the interests of stakeholders. The introduction of national and EU regulated procurement methods such as the Most Economically Advantageous Tenders (MEAT), has opened the way towards a more active and balanced involvement of actors and stakeholders in the development and realisation of urban construction projects. In this new environment, the client, consultant, contractor and stakeholders strive to work together in order to realise a sustainable solution. This document describes a methodology for the management of project processes with the aim of achieving a lawful, effective and sustainable construction process. The methodology is based on the principle of Life Cycle Systems Engineering, and facilitates and structures the introduction of sustainability and stakeholders issues in the design and build process. The method uses manly existing guidelines and standards for Life Cycle Systems Engineering

Predicting project performance using pre-construction performance indicators - A case study evaluation

Predicting the outcome of a construction project largely relies on estimated targets of time and cost. Still, hitting the targets does not mean that the project is a success on all performance levels. Here, a retrospective case study was undertaken on a construction project identified as a successful project by the partners involved. The purpose of the study was to validate conceptual design indicators of a high-performance construction project as reported in the literature, by answering the following research questions: "What characterizes the dialogue between the different disciplines; (2) What is the dialogue about; and (3) When in the process do questions arise?" Findings indicate that the interprofessional dialogue within the project team was well established. The paper introduces a discussion that the dialogue benefited from the collaborative project environment as well as the early design intent. Further, the study also suggests that the interprofessional dialogue supported a sound project team development

The Impact of Lanthanum and Zeolite Structure on Hydrocarbon Storage

Hydrocarbon traps can be used to bridge the temperature gap from the cold start of a vehicle until the exhaust after-treatment catalyst has reached its operating temperature. In this work, we investigate the effect of zeolite structure (ZSM-5, BEA, SSZ-13) and the effect of La addition to H-BEA and H-ZSM-5 on the hydrocarbon storage capacity by temperature-programmed desorption and DRIFT spectroscopy. The results show that the presence of La has a significant effect on the adsorption characteristics of toluene on the BEA-supported La materials. A low loading of La onto zeolite BEA (2% La-BEA) improves not only the toluene adsorption capacity but also the retention of toluene. However, a higher loading of La results in a decrease in the adsorbed amount of toluene, which likely is due to partial blocking of the pore of the support. High loadings of La in BEA result in a contraction of the unit cell of the zeolite as evidenced by XRD. A synergetic effect of having simultaneously different types of hydrocarbons (toluene, propene, and propane) in the feed is found for samples containing ZSM-5, where the desorption temperature of propane increases, and the quantity that desorbed increases by a factor of four. This is found to be due to the interaction between toluene and propane inside the structure of the zeolite

Multi-criteria decision analysis methods to support sustainable infrastructure construction

The construction of infrastructure projects represents a large sustainability impact, both positive and negative. Increased positive and reduced negative impacts can be achieved through better design and planning of the construction. To make more sustainable choices, well‐defined predictive sustainability assessment methods are required. Multi‐criteria decision analysis (MCDA) is a well-suited method for predictive sustainability assessment. This paper evaluates two MCDA methods for sustainability assessment of infrastructure construction and exemplifies their application with two case studies. The aim of this paper is to discuss if the methods are suitable for identifying the most sustainable alternative during the procurement process of an infrastructure project. It is recommended that MCDA methods are further developed to comply with the recently published EN standard on sustainability assessment of civil engineering works

Gas-phase phosphorous poisoning of a Pt/Ba/Al2O3 NOx storage catalyst

The effect of phosphorous exposure on the NO x storage capacity of a Pt/Ba/Al 2 O 3 catalyst coated on a ceramic monolith substrate has been studied. The catalyst was exposed to phosphorous by evaporating phosphoric acid in presence of H 2 O and O 2 . The NOx storage capacity was measured before and after the phosphorus exposure and a significant loss of the NO x storage capacity was detected after phosphorous exposure. The phosphorous poisoned samples were characterized by X-ray photoelectron spectroscopy (XPS), environmental scanning electron microscopy (ESEM), N 2 -physisorption and inductive coupled plasma atomic emission spectroscopy (ICP-AES). All characterization methods showed an axial distribution of phosphorous ranging from the inlet to the outlet of the coated monolith samples with a higher concentration at the inlet of the samples. Elemental analysis, using ICP-AES, confirmed this distribution of phosphorous on the catalyst surface. The specific surface area and pore volume were significantly lower at the inlet section of the monolith where the phosphorous concentration was higher, and higher at the outlet where the phosphorous concentration was lower. The results from the XPS and scanning electron microscopy (SEM)-energy dispersive X-ray (EDX) analyses showed higher accumulation of phosphorus towards the surface of the catalyst at the inlet of the monolith and the phosphorus was to a large extent present in the form of P 4 O 10 . However, in the middle section of the monolith, the XPS analysis revealed the presence of more metaphosphate (PO 3 – ). Moreover, the SEM-EDX analysis showed that the phosphorous to higher extent had diffused into the washcoat and was less accumulated at the surface close to the outlet of the sampl

Assessing Land Degradation/Recovery in the African Sahel from Long-Term Earth Observation Based Primary Productivity and Precipitation Relationships

The ‘rain use efficiency’ (RUE) may be defined as the ratio of above-ground net primary productivity (ANPP) to annual precipitation, and it is claimed to be a conservative property of the vegetation cover in drylands, if the vegetation cover is not subject to non-precipitation related land degradation. Consequently, RUE may be regarded as means of normalizing ANPP for the impact of annual precipitation, and as an indicator of non-precipitation related land degradation. Large scale and long term identification and monitoring of land degradation in drylands, such as the Sahel, can only be achieved by use of Earth Observation (EO) data. This paper demonstrates that the use of the standard EO-based proxy for ANPP, summed normalized difference vegetation index (NDVI) (National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) Global Inventory Modeling and Mapping Studies 3rd generation (GIMMS3g)) over the year (ΣNDVI), and the blended EO/rain gauge based data-set for annual precipitation (Climate Prediction Center Merged Analysis of Precipitation, CMAP) results in RUE-estimates which are highly correlated with precipitation, rendering RUE useless as a means of normalizing for the impact of annual precipitation on ANPP. By replacing ΣNDVI by a ‘small NDVI integral’, covering only the rainy season and counting only the increase of NDVI relative to some reference level, this problem is solved. Using this approach, RUE is calculated for the period 1982–2010. The result is that positive RUE-trends dominate in most of the Sahel, indicating that non-precipitation related land degradation is not a widespread phenomenon. Furthermore, it is argued that two preconditions need to be fulfilled in order to obtain meaningful results from the RUE temporal trend analysis: First, there must be a significant positive linear correlation between annual precipitation and the ANPP proxy applied. Second, there must be a near-zero correlation between RUE and annual precipitation. Thirty-seven percent of the pixels in Sahel satisfy these requirements and the paper points to a range of different reasons why this may be the case