Investigation of cylinder deactivation and variable valve actuation on gasoline engine performance

Increasingly stringent regulations on gasoline engine fuel consumption and exhaust emissions require additional technology integration such as Cylinder Deactivation (CDA) and Variable valve actuation (VVA) to improve part load engine efficiency. At part load, CDA is achieved by closing the inlet and exhaust valves and shutting off the fuel supply to a selected number of cylinders. Variable valve actuation (VVA) enables the cylinder gas exchange process to be optimised for different engine speeds by changing valve opening and closing times as well as maximum valve lift. The focus of this study was the investigation of effect of the integration of the above two technologies on the performance of a gasoline engine operating at part load conditions. In this study, a 1.6 Litre in-line 4-cylinder gasoline engine is modelled on engine simulation software and simulated data is analysed to show improvements in fuel consumption, CO2 emissions, pumping losses and effects on CO and NOx emissions. A CDA and VVA operating window is identified which yields brake specific fuel consumption improvements of 10-20% against the base engine at engine speeds between 1000rpm to 3500rpm at approximately 12.5% load. Highest concentration of CO emissions was observed at between 4 to 5 bar BMEP at 4000rpm and highest concentration of NOx at the same load range but at 1000rpm.Findings based on simulation results point towards significant part load performance improvements which can be achieved by integrating cylinder deactivation and variable valve actuation on gasoline engines. Copyright © 2014 SAE International

Understanding the adaptive capacity of Australian small-to-medium enterprises to climate change and variability

Abstract Small-to-medium enterprises (SMEs) comprise 96 per cent of all private businesses in Australia. The SME sector is the economy’s largest employer and the largest contributor to GDP. Moreover, SMEs play a significant role within socio-economic systems: they provide employment, goods and services and tax revenue for communities. Climate change may result in adverse business outcomes including business interruptions, increased investment and insurance costs, and declines in financial indicators such as measures of value, return and growth. After natural disasters, SMEs face greater short-term losses than larger enterprises, and may have lower adaptive capacity for various reasons. This study examines the underlying factors and processes shaping adaptive capacity of Australian SMEs’ to climate change and associated sea level rise. Specifically, the research asks the following questions: 1) How have SMEs considered and integrated adaptation into business planning? 2) What are the key underlying processes that constrain and influence the adaptive capacities of SMEs? and 3) What types of support are required to promote SME business continuity under a changing climate? The study adopts theories from Political Ecology and draws on literature on vulnerability and hazards to understand the processes that mediate the adaptive capacity of SMEs. The empirical research involved an online survey targeting SMEs, attending business engagement events hosted by chambers of commerce, 30 semi-structured interviews with secondary stakeholders, five case studies involving SMEs and secondary stakeholders, and finally a stakeholder workshop which brought together participants from both groups. The central conclusion of this study is that underlying contextual processes are critical to enhancing the adaptive capacity of SMEs. These processes include: the social relationships between SMEs and support organisations; the relationships within support organisations themselves; the agency of SMEs to direct resources toward building resilience into business continuity; SMEs’ perceptions of climate risks; and power struggles between support organisations. Unfavourable combinations of these processes have the potential to limit the adaptive choices that SMEs can adopt in order to overcome climate change and other related stresses on business continuity. These processes generate vulnerability and often occur at scales external to the SMEs;including relationships between different tiers of government as well as between various support organisations working with SMEs. These contextual processes have been largely overlooked in formal programmes that aim to build business resilience. The programmes have tended to be reactive and have tended to focus on business recovery during and after disasters rather than on altering the vulnerability context of SMEs through anticipatory prevention and preparedness or adaptation planning. This study suggests that the success of efforts to build the adaptive capacity of SMEs to future climate and related stresses will depend on how they address these underlying processes to facilitate the ability of SMEs to exercise their agency in pursuing adaptive choices that they value

Barriers to reducing climate enhanced disaster risks in least developed country-small islands through anticipatory adaptation

© 2014 The Authors. Small Island Developing States (SIDS) classified as Least Developed Countries (LDCs) are particularly vulnerable to the projected impacts of climate change. Given their particular vulnerabilities, climate adaptation investments are being made through both national and international efforts to build the capacity of various sectors and communities to reduce climate risks and associated disasters. Despite these efforts, reducing climate risks is not free of various challenges and barriers. This paper aims to synthesise a set of critical socio-economic barriers present at various spatial scales that are specific to Least Developed Country SIDS. It also aims to identify the processes that give rise to these barriers. Drawing on theories from natural hazards, a systematic literature review method was adopted to identify and organise the set of barriers by focussing on both academic papers and grey literature. The data revealed a notable lack of studies on adaptation within African and Caribbean LDC-SIDS. In general, there was a paucity of academic as well as grey literature being produced by authors from LDC-SIDS to challenge existing discourses related to adaptation barriers. The most common barriers identified included those related to governance, technical, cognitive and cultural. Three key findings can be drawn from this study in relation to formal adaptation initiatives. Firstly, the lack of focus on the adaptive capacity needs of Local Government or Island Councils and communities was a key barrier to ensure success of adaptation interventions. Secondly, international adaptation funding modalities did little to address root causes of vulnerability or support system transformations. These funds were geared at supporting sectoral level adaptation initiatives for vulnerable natural resource sectors such as water, biodiversity and coastal zones. Thirdly, there is a need to recognise the significance of cultural knowledge and practices in shaping adaptive choices of communities in SIDS

Consumer intention toward online grocery shopping during the post-pandemic (Covid-19)

Purpose: The study investigates the factors that influence consumers’ online grocery purchase intention during the post-pandemic of Covid-19 in Sri Lanka. Design/methodology/approach: Primary data was collected using a pre-tested structured questionnaire. Data was gathered based on 5 variables and the Confirmatory Factor Analysis (CFA) and Structural Equation Modelling (SEM) were applied to analyze the empirical data of 200 respondents. And twenty-five indicators were used to measure the five variables. Further, the study uses Statistical Package for the Social Sciences (SPSS 25) and Analysis of Moment Structures (AMOS 26) to conduct the analysis. Findings: The study found significant factors that affect consumers’ online grocery purchase intention. The results revealed that Perceived Ease of Use and Perceived Usefulness have a positive and significant impact on the online Purchase Intention of consumers while Perceived Risk represents a negative and insignificant effect on the online grocery purchase intention of consumers. Further, Hedonic Motivation did not affect the online purchase intention of consumers. Originality: This study represents the online grocery purchase intention among consumers by investigating consumer behavior during and after the Covid-19 pandemic by using the technology acceptance model as a guiding theory. Implications: The research is based on the expansion of the Technology Acceptance Model (TAM). Besides, the variable “perceived risk” is added to identify the factors that affect consumers’ online shopping intentions. The study confirmed the significant influence of perceived usefulness, perceived ease of use, and hedonic motivation on the continuance usage of online grocery purchasing during the post-pandemic of Covid-19. Moreover, online retailers should improve their online platforms to address the consumers’ increasing demand for online grocery purchasing. Keywords: Online grocery shopping, Post pandemic, Structural equation modeling, Technology acceptance model &nbsp

Synthesis and Characterization of Tannin Based Porous Cation Exchange Resins from Cassia auriculata (Ranawara)

Tannins are one of the most abundant compounds in the nature. Naturally tannins have ion exchanging capability. Conversely, tannins are highly water soluble compounds, thus natural tannins cannot be used as ion exchangers. In this study, tannins extracted from Cassia auriculata (Ranawara) were used to synthesise renewable tannin based porous cation exchange resin systems. Essentially, the applicability of these resin systems as an ion exchange resin were considered. Identification of the Tannin was carried out by using ferric chloride test, nitrous acid test and acid butanol tests. Total polyphenolic content of Cassia auriculata was 13.30% (w/w) and it was calculated by using Folin-ciocalteau method. Tannin-Formaldehyde resin was prepared, and the ion exchange capacity was measured. Then the Tannin-Formaldehyde resin was sulfonated to increase the ion exchange capacity by refluxing with concentrated H2SO4. Then, the ion exchange capacity of the resin was further increased by introducing a porous structure using virgin coconut oil as the porogenic agent. Ion exchange capacity, solubility, Fourier transform infrared spectroscopy and scanning electron microscopy analysis were used to characterise the resin systems. The modified resin with high fraction of surfactant contains mostly open porous structures and it has the highest IEC (0.9550 meq/g) among the synthesized resin systems.Keywords: Cassia auriculata (Ranawara), porous tannin-formaldehyde cation exchange resin, ion exchange capacity, FTIR, SE

Regional stability changes in oxidized and reduced cytochrome c located by hydrogen exchange and mass spectrometry

Amide hydrogen exchange rates are highly sensitive to protein structure and may, therefore, be used to detect and characterize structural changes in proteins. Specific regions within folded proteins undergoing structural change can often be identified if localized amide hydrogen exchange rates are determined by nuclear magnetic resonance (NMR). The ability to measure localized amide hydrogen exchange rates by proteolytic fragmentation followed by mass spectrometric analysis opens the possibility to also identify localized structural changes in proteins by mass spectrometry. If successful, this approach offers considerable advantage over NMR in speed, sensitivity, protein solubility, and ability to study large proteins. This possibility has been investigated by determining the amide hydrogen exchange rates in oxidized and reduced cytochrome c by protein fragmentation/mass spectrometry. The fundamental difference in these forms of cytochrome c is the oxidation state of the iron, which other studies have shown results in only minor structural changes in the protein. In the present study, the largest differences in hydrogen exchange rates were found for peptide amide hydrogens located distant from the Nand C-termini, indicating that the structure in these regions is most affected by the oxidation state of the iron. These results are consistent with previous studies of oxidized and reduced cytochrome c, suggesting that hydrogen exchange and mass spectrometry may be generally useful for locating subtle changes in protein structure

Chemical Approaches for Nanofabrication Based on Colloidal Lithography with Organosilanes, Nanoparticles and Nickel Films: The Role of Water in Directing Surface Self-Assembly

The capabilities for accomplishing fundamental surface studies with molecular systems are demonstrated in this dissertation using measurement and imaging modes of scanning probe microscopy. Model systems were chosen for investigations of surface self-assembly mechanisms, with an emphasis on understanding the role of interfacial water in surface reactivity. A key strategy for molecular level studies was to prepare nanostructures using protocols with colloidal lithography and scanning probe-based lithography (SPL). Nanofabricated samples were characterized ex situ with contact and tapping-mode atomic force microscopy (AFM) after key reaction steps, providing direct views of changes in surface morphology at the nanoscale. Magnetic sample modulation (MSM) combined with contact mode AFM provided a route to detect the vibration of magnetic nanomaterials in response to an externally applied electromagnetic field. Nanoscale measurements of the size-scaling effects for physical properties such as conductance and nanomagnetism are contemporary topics in the field of nanoscience. Protocols of SPL were used for studies with organic thin films; nanoshaving and nanografting experiments provided a means to prepare ultra-small nanostructures. Nickel-coated nanostructures were constructed on amine-terminated nanorings of aminopropyltriethoxysilane (APTES) using colloidal lithography and chemical steps of electroless deposition (ELD), nickel was deposited by an autocatalytic redox reaction using palladium as a catalyst. Protocols were developed to investigate the role of water in the association and placement of silane molecules on surfaces as a strategy for indirectly tracking the location of water on surfaces. Visible light photocatalysis was used to prepare nanostructured films by immersing surface masks of monodisperse spheres in solutions of an aryl halide and then irradiating the solution with blue light. Films of aryl halide are linked to the surface by C-Au bonds to form robust films that resist the effects of oxidation. Nanostructured films of octaethylporphyrin (OEP) were prepared with immersion particle lithography by reaction with silicon tetrachloride. Porphyrins bound to the surface through covalent Si-O-surface linkages coordinated to the centers of the macrocycles in a kebob arrangement. The Si-O-Si “skewer” strategy was also successful for encapsulating Au nanoparticles with porphyrins to make core-shell nanoparticles. Fundamental studies targeted questions related to controlling surface assembly and interfacial chemistry details