Mechanical behaviours of pumpkin peel under compression test

Mechanical damages such as bruising, collision and impact during food processing stages diminish quality and quantity of productions as well as efficiency of operations. Studying mechanical characteristics of food materials will help to enhance current industrial practices. Mechanical properties of fruits and vegetables describe how these materials behave under loading in real industrial operations. Optimizing and designing more efficient equipments require accurate and precise information of tissue behaviours. FE modelling of food industrial processes is an effective method of studying interrelation of variables during mechanical operation. In this study, empirical investigation has been done on mechanical properties of pumpkin peel. The test was a part of FE modelling and simulation of mechanical peeling stage of tough skinned vegetables. The compression test has been conducted on Jap variety of pumpkin. Additionally, stress strain curve, bio-yield and toughness of pumpkin skin have been calculated. The required energy for reaching bio-yield point was 493.75, 507.71 and 451.71 N.mm for 1.25, 10 and 20 mm/min loading speed respectively. Average value of force in bio-yield point for pumpkin peel was 310 N.

Loving Europe : Charmian Clift, Peel Me a Lotus, and Australian women writing travel

“There it went!—Our last little bit of capital, our going back to civilization money . . .” So Charmian Clift fretted when she watched her husband George Johnson hand over a large number of drachma notes to buy a house on the Greek Island of Hydra in 1956. Whereas today’s expatriates fly back and forth between home and away with ease, Clift’s commitment to Hydra meant that a return to Australia, “to civilization”, would always be difficult and perhaps impossible...

Tensile properties of pumpkin peel and flesh tissue and review of current testing methods

In South and Southeast Asia, postharvest loss causes material waste of up to 66% in fruits and vegetables, 30% in oilseeds and pulses, and 49% in roots and tubers. The efficiency of postharvest equipment directly affects industrial-scale food production. To enhance current processing methods and devices, it is essential to analyze the responses of food materials under loading operations. Food materials undergo different types of mechanical loading during postharvest and processing stages. Therefore, it is important to determine the properties of these materials under different types of loads, such as tensile, compression, and indentation. This study presents a comprehensive analysis of the available literature on the tensile properties of different food samples. The aim of this review was to categorize the available methods of tensile testing for agricultural crops and food materials to investigate an appropriate sample size and tensile test method. The results were then applied to perform tensile tests on pumpkin flesh and peel samples, in particular on arc-sided samples at a constant loading rate of 20 mm min-1. The results showed the maximum tensile stress of pumpkin flesh and peel samples to be 0.535 and 1.45 MPa, respectively. The elastic modulus of the flesh and peel samples was 6.82 and 25.2 MPa, respectively, while the failure modulus values were 14.51 and 30.88 MPa, respectively. The results of the tensile tests were also used to develop a finite element model of mechanical peeling of tough-skinned vegetables. However, to study the effects of deformation rate, moisture content, and texture of the tissue on the tensile responses of food materials, more investigation needs to be done in the future.

A constitutive model for mechanical response characterization of pumpkin peel and flesh tissues under tensile and compressive loadings

Enhancing quality of food products and reducing volume of waste during mechanical operations of food industry requires a comprehensive knowledge of material response under loadings. While research has focused on mechanical response of food material, the volume of waste after harvesting and during processing stages is still considerably high in both developing and developed countries. This research aims to develop and evaluate a constitutive model of mechanical response of tough skinned vegetables under postharvest and processing operations. The model focuses on both tensile and compressive properties of pumpkin flesh and peel tissues where the behaviours of these tissues vary depending on various factors such as rheological response and cellular structure. Both elastic and plastic response of tissue were considered in the modelling process and finite elasticity combined with pseudo elasticity theory was applied to generate the model. The outcomes were then validated using the published results of experimental work on pumpkin flesh and peel under uniaxial tensile and compression. The constitutive coefficients for peel under tensile test was α = 25.66 and β = −18.48 Mpa and for flesh α = −5.29 and β = 5.27 Mpa. under compression the constitutive coefficients were α = 4.74 and β = −1.71 Mpa for peel and α = 0.76 and β = −1.86 Mpa for flesh samples. Constitutive curves predicted the values of force precisely and close to the experimental values. The curves were fit for whole stress versus strain curve as well as a section of curve up to bio yield point. The modelling outputs had presented good agreement with the empirical values and the constructive curves exhibited a very similar pattern to the experimental curves. The presented constitutive model can be applied next to other agricultural materials under loading in future.

Remembering the Peel Island Lazaret through re-imagining the Teerk Roo Ra forest

This paper discusses my current research which aims to re-member the site of the Peel Island Lazaret through re-imagining the Teerk Roo Ra forest as a series of animated artworks. Teerk Roo Ra National Park (formally known as Peel Island) is a small island in Moreton Bay, Queensland and is visible on the ferry journey from Cleveland to Stradbroke Island. The island has an intriguing history, and is the site of a former Lazaret and quarantine station. The Lazaret treated patients diagnosed with Hansen’s disease (or Leprosy), and operated between 1907 and 1959. In this paper I will discuss conceptions of the non-indigenous historical context of the Peel Island Lazaret and the notion of the liminal state (Turner,1967). Through this discussion conceptions of place from Australian cultural theorist Ross Gibson are also examined. The concept of two overlapping realms is then explored through the clues and shared stories about the people who inhabited the site. There is then an explanation of my own approach to re-member this place through re-imagining the forest that witnessed the events of the Lazaret. I then draw on theories of the uncanny from German Psychiatrist Ernst Jentsch, Austrian Neurologist Sigmund Freud and South African animation theorist Meg Rickards to argue that my experience of the forest of Teerk Roo Ra was an uncanny experience where two worlds or states of mind existed simultaneously and overlapped, causing a viscerally unsettling uncanny experience. Through an analysis of Czech Surrealist Animator Jan Švankmajer’s cinematic narrative Down to the cellar (1982), my creative work Structure #24(2011), and Australian Artist Patricia Piccinini’s cinematic artwork The Gathering (2007), I discuss the situation of the inanimate and the animate co-existing simultaneously. Using this approach I propose an understanding of the uncanny as an intellectual uncertainty as outlined by Jentsch (1906). I also develop the notion of the familiar being concealed and becoming unfamiliar through mimicry (Freud, 1919). These discussions form an introduction to my creative work Nocturne #5(2014) which re-members the forests of Teerk Roo Ra as an uncanny place primarily expressed through animation.

Apprehending the void: Using animation to interpret the genius loci of the Peel Island Lazaret

This practice-led research project harnesses the plasmatic nature of animation (Eisenstein 1989) to embody the in-between state of being of the Peel Island Lazaret on the island of Teerk Roo Ra in Moreton Bay, Queensland. In this project the genius loci of this place is expressed through the development of a series of creative works that employs the unique transformative quality of animation to push and pull at the boundary lines between what can be apprehended as the ‘real’ and the ‘imaginary’. Drawing on the physical approach of Czech surrealist animator Jan Švankmajer and cultural theories from Australian writer Ross Gibson, this study re-members and re-imagines the site of the Lazaret as a liminal, uncanny place. This study investigates how conceptions of place are overlaid by aspects of history, memory and the imagination and these discoveries contribute to the currently limited academic discourse around place and place-making in animation practice in Australia.

The ILC's Articles on Responsibility of States for Internationally Wrongful Acts: Completion of the Second Reading

In 2001 the International Law Commission finally adopted on second reading the Draft Articles on Responsibility of States for Internationally Wrongful Acts with commentaries, bringing to an end nearly 50 years of ILC work on the subject. This article reviews the final group of changes to the text, focusing on the definitions of ‘injury’ and ‘damage’, assurances of non‐repetition in the light of the LaGrand case, procedural aspects of countermeasures and the controversy over measures taken in response to a breach by states which are not individually injured. The focus of debate now turns to the UNGA Sixth Committee, which will have to decide what to make of the Draft Articles. The ILC itself recommended an initial resolution taking note of the Articles, with subsequent consideration (after a period of years) of a possible diplomatic conference with a view to concluding a convention. This modest proposal allows for further reflection on the text and may help to avoid possibly divisive and inconclusive debate in the Sixth Committee. At the same time it allows time for better understanding of the many changes made as compared with the first reading text (1996).

Questions of English : ethics, aesthetics, rhetoric, and the formation of the subject in England, Australia and the United States

The impact and content of English as a subject on the curriculum is once more the subject of lively debate. Questions of English sets out to map the development of English as a subject and how it has come to encompass the diversity of ideas that currently characterise it. Drawing on a combination of historical analysis and recent research findings Robin Peel, Annette Patterson and Jeanne Gerlach bring together and compare important new insights on curriculum development and teaching practice from England, Australia and the United States. They also discuss the development of teacher training, highlighting the variety of ways in which teachers build their own beliefs and knowledge about English.

Experimental study on mechanical properties of pumpkin tissue

Purpose: The purpose of this study was to calculate mechanical properties of tough skinned vegetables as a part of Finite Element Modelling (FEM) and simulation of tissue damage during mechanical peeling of tough skinned vegetables. Design/methodology: There are some previous studies on mechanical properties of fruits and vegetables however, behaviour of tissue under different processing operations will be different. In this study indentation test was performed on Peel, Flesh and Unpeeled samples of pumpkin as a tough skinned vegetable. Additionally, the test performed in three different loading rates for peel: 1.25, 10, 20 mm/min and 20 mm/min for flesh and unpeeled samples respectively. The spherical end indenter with 8mm diameter used for the experimental tests. Samples prepare from defect free and ripped pumpkin purchased from local shops in Brisbane, Australia. Humidity and temperature were 20-55% and 20-250C respectively. Findings: Consequently, force deformation and stress and strain of samples were calculated and shown in presented figures. Relative contribution (%) of skin to different mechanical properties is computed and compared with data available from literature. According the results, peel samples had the highest value of rupture force (291N) and as well as highest value of firmness (1411Nm-1). Research limitations/implications: The proposed study focused on one type of tough skinned vegetables and one variety of pumpkin however, more tests will give better understandings of behaviours of tissue. Additionally, the behaviours of peel, unpeeled and flesh samples in different speed of loading will provide more details of tissue damages during mechanical loading. Originality/value: Mechanical properties of pumpkin tissue calculated using the results of indentation test, specifically the behaviours of peel, flesh and unpeeled samples were explored which is a new approach in Finite Element Modelling (FEM) of food processes. Keywords: Finite Element Modelling (FEM), relative contribution, firmness, toughness and rupture force.

Properties of tough skinned vegetable-pumpkin tissue

Understanding of mechanical behaviour of food particles will provide researchers and designers essential knowledge to improve and optimise current food industrial technologies. Understanding of tissue behaviours will lead to the reduction of material loss and enhance energy efficiency during processing operations. Although, there are some previous studies on properties of fruits and vegetables however, tissue behaviour under different processing operations will be different. The presented paper is a part of FE modelling and simulation of tissue damage during mechanical peeling of tough skinned vegetables. In this study indentation test was performed on peeled and unpeeled samples at loading rate of 20 mm/min for peel, flesh and unpeeled samples. Consequently, force deformation and stress and strain of samples were calculated. The toughness of the tissue also has been calculated and compared with the previous results.

Five commercial citrus rate poorly as hosts of the polyphagous fruit flyBactrocera tryoni(Froggatt) (Diptera: Tephritidae) in laboratory studies

Queensland fruit fly, Bactrocera tryoni (Froggatt), is a polyphagous pest, and many citrus types are included among its hosts. While quantification of citrus host use by B. tryoni is lacking, citrus is generally considered a ‘low pressure’ crop. This paper investigates B. tryoni female oviposition preference and offspring performance in five citrus types; Murcott mandarin (Citrus reticulata), Navel orange and Valencia orange (Citrus sinensis), Eureka lemon (Citrus limon) and yellow grapefruit (Citrus paradisi). Oviposition preference was investigated in laboratory-based choice and no-choice experiments, while immature survival and offspring performance were investigated by infesting fruits in the laboratory and evaluating pupal recovery, pupal emergence and F1 fecundity. Fruit size, Brix level and peel toughness were also measured for correlation with host use. Bactrocera tryoni demonstrated an oviposition preference hierarchy among the citrus fruits tested; Murcott and grapefruit were most preferred for oviposition and lemon the least, while preference for Navel and Valencia was intermediate. Peel toughness was negatively correlated with B. tryoni oviposition preference, while no significant correlations were detected between oviposition and Brix level or fruit size. Immature survival in the tested fruit was very low. Murcott was the best host (21% pupal recovery), while all other citrus types that showed pupal recovery of 6% or lower and no pupae were recovered from Valencia orange. In pupae recovered from Navel orange and lemon, adult eclosion was greatly reduced, while in grapefruit and lemon, no eggs were recovered from F1 adults. Based on these laboratory results, many commercial citrus varieties appear to be poor hosts for B. tryoni and may pose a low post-harvest and quarantine risk. These findings need to be confirmed in the field, as they impact on both pre-harvest and post-harvest countermeasures.

Second Skin 2012 Workshop

The Second Skin 2012 Workshop Program consisted of a full-day intensive design immersion workshop run on Saturday 14 July 2012, at the QUT Faculty of Creative Industries Fashion Studios at Kelvin Grove Brisbane, Australia, for 30? self-selected high-achieving junior and middle school (year 5-9) students, as part of the Queensland Academies ‘Young Scholars’ Program. Inspired by a scientist researching the impact of sun on skin, and mentored by tertiary fashion design and interior design educators, and six tertiary fashion design and interior design students, the workshop explored science and design-inspired prototype solutions for sun-safety. This action research study aimed to facilitate an acute awareness in young people of the sun safety message (alternative to a scare campaign), the role of design in society and the value of design thinking skills in solving complex challenges, and to inspire the generation of strategies to address a systemic health issue. It also aimed to investigate the value of collaboration between junior and middle school students, tertiary design educators and students and industry professionals in targeting youth sun safety, and inspiring post-secondary pathways and idea generation for education. During the workshop, students developed sketching, making, communication, presentation and collaboration skills to improve their design process, while considering social, cultural and environmental opportunities. Through a series of hands-on collaborative design experiments, participants explored in teams of five, ways in which a ‘second skin’ can mirror elements of our skin – the ability to protect, divide, enclose, stretch, scar, pattern, peel and reveal – inspiring both functional and aesthetic design solutions. Underpinned by the State Library of Queensland Design Minds Website ‘inquire, ideate and implement’ model of design thinking, the experiments culminated in the development of a detailed client brief, the design and fabrication of a fashionable sun safe clothing range and then a team presentation and modelling of prototypes in a fashion parade, viewed also by parents. The final collections were judged by three prominent judges: Louise Baldwin - Executive Manager Public Health QLD Cancer Council, Shane Thompson - Architect and 2012 Queensland Smart Design Fellow, and Leigh Buchanan – Fashion designer and Project Runway Australia finalist. The workshop was filmed for Queensland television program ‘Totally Wild’ for dissemination of the value of design, the Design Minds model and the sun safety message to a wider target youth audience.