3D roll-forming of hat-profile with variable depth and width

The use of roll-formed products in automotive, furniture, buildings etc. increases every year due to the low part-production cost and the complicated cross-sections that can be produced. The limitation with roll-forming until recent years is that one could only produce profiles with a constant cross-section in the longitudinal direction. About eight years ago ORTIC AB [1] developed a machine in which it was possible to produce profiles with a variable width (“3D roll-forming”) for the building industry. Experimental equipment was recently built for research and prototyping of profiles with variable cross-section in both width and depth for the automotive industry. The objective with the current study is to investigate the new tooling concept that makes it possible to roll-form hat-profiles, made of ultra high strength steel, with variable cross-section in depth and width. The result shows that it is possible to produce 3D roll-formed profiles with close tolerances.

Calcium- and vitamin D3 - fortified milk reduces bone loss at clinically relevant skeletal sites on llder men: a 2-year randomised controlled trial

In this 2-year randomized controlled study of 167 men >50 years of age, supplementation with calcium-vitamin D3-fortified milk providing an additional 1000 mg of calcium and 800 IU of vitamin D3 per day was effective for suppressing PTH and stopping or slowing bone loss at several clinically important skeletal sites at risk for fracture.

Introduction: Low dietary calcium and inadequate vitamin D stores have long been implicated in age-related bone loss and osteoporosis. The aim of this study was to assess the effects of calcium and vitamin D3 fortified milk on BMD in community living men >50 years of age.

Materials and Methods: This was a 2-year randomized controlled study in which 167 men (mean age ± SD, 61.9 ± 7.7 years) were assigned to receive either 400 ml/day of reduced fat (1%) ultra-high temperature (UHT) milk containing 1000 mg of calcium plus 800 IU of vitamin D3 or to a control group receiving no additional milk. Primary endpoints were changes in BMD, serum 25(OH)D, and PTH.

Results: One hundred forty-nine men completed the study. Baseline characteristics between the groups were not different; mean dietary calcium and serum 25(OH)D levels were 941 ± 387 mg/day and 77 ± 23 nM, respectively. After 2 years, the mean percent change in BMD was 0.9-1.6% less in the milk supplementation compared with control group at the femoral neck, total hip, and ultradistal radius (range, p < 0.08 to p < 0.001 after adjusting for covariates). There was a greater increase in lumbar spine BMD in the milk supplementation group after 12 and 18 months (0.8-1.0%, p ≤ 0.05), but the between-group difference was not significant after 2 years (0.7%; 95% CI, −0.3, 1.7). Serum 25(OH)D increased and PTH decreased in the milk supplementation relative to control group after the first year (31% and −18%, respectively; both p < 0.001), and these differences remained after 2 years. Body weight remained unchanged in both groups at the completion of the study.

Conclusions: Supplementing the diet of men >50 years of age with reduced-fat calcium- and vitamin D3-enriched milk may represent a simple, nutritionally sound and cost-effective strategy to reduce age-related bone loss at several skeletal sites at risk for fracture in the elderly.

Structured methodology for evaluating stamping feasibility of new part design

With the introduction of ultra high strength materials and new forming techniques the feasibility process to produce a manufacturable component is extremely difficult. The aim of this thesis was to develop a set of 'design windows' and 'guidelines' for designers and stamping engineers to reference in the initial design phase.

1H-NMR and mass spectrometric characterization of the metabolic response of juvenile Atlantic salmon (Salmo salar) to long-term handling stress

Stressors of various kinds constantly affect fish both in the wild and in culture, examples being acute water temperature and quality changes, predation, handling, and confinement. Known physiological responses of fish to stress such as increases in plasma cortisol and glucose levels, are considered to be adaptive, allowing the animal to cope in the short term. Prolonged exposure to stressors however, has the potential to affect growth, immune function, and survival. Nonetheless, little is known about the mechanisms underlying the long-term stress response. We have investigated the metabolic response of juvenile Atlantic salmon (Salmo salar) to long-term handling stress by analyzing fish plasma via ¹H nuclear magnetic resonance spectroscopy and ultra high performance liquid chromatography–mass spectrometry (UPLC–MS), and comparing results with controls. Analysis of NMR data indicated a difference in the metabolic profiles of control and stressed fish after 1 week of stress with a maximum difference observed after 2 weeks. These differences were associated with stress-induced increases in phosphatidyl choline, lactate, carbohydrates, alanine, valine and trimethylamine-N-oxide, and decreases in low density lipoprotein, very low density lipoprotein, and lipid. UPLC-MS data showed differences at week 2, associated with another set of compounds, tentatively identified on the basis of their mass/charge. Overall the results provided a multi-faceted view of the response of fish to long-term handling stress, indicating that the metabolic disparity between the control and stress groups increased to week 2, but declined by weeks 3 and 4, and revealed several new molecular indicators of long-term stress.

Understanding in-vivo abrasion fatigue or common suture materials used in arthroscopic and open shoulder surgery

In orthopaedic surgery the reattachment of tendon to bone requires suture materials that have stable and durable properties to allow healing at the tendon-bone interface. Failure rates of this type of surgery can be as high as 25%. While the tissue suture interface is a weak link, proportions of these failures are caused by in-vivo abrasion of the suture with bone and suture anchor materials. Abrasion of the suture material results from the movement of the suture through the eyelet by the surgeon during surgery, or with limb movement after surgery as the suture is not rigidly restrained within the eyelet. During movement the suture is subjected to bending and frictional forces that can lead to fatigue induced failure. This paper investigates the mechanism of bending abrasion fatigue induced failure of number two grade braided sheath only and braided sheath/multifilament core sutures. Sutures were oscillated over a stainless steel wire at low frequency under load in a dry state to simulate the bending and frictional forces between suture and eyelet. Failure mechanism was determined by video microscopy of the suture during abrasion combined with optical microscopy analysis of partially and fully abraded sutures. Braided only structures had high friction loading on the small number of fibres at the abrasion interface. This caused rapid single fibre breakages that accumulate to cause suture failure. The addition of ultra-high molecular weight polyethylene core fibres to a braided suture distributed the applied load across multiple fibres at the abrasion interface. This improved abrasion resistance by 15-20 times that of braided sheath alone.

Approach for testing the material behavior in roll forming in a small scale

Roll forming of ultra-high strength steels (UHSS) and other high strength alloys is an advanced manufacturing methodology with the ability of cold forming those materials to complex three-dimensional shapes for lightweight structural applications. Due to their high strength, most of these materials have a reduced ductility which excludes conventional sheet forming methods under cold forming conditions. Roll forming is possible due to its low strains and incremental forming characteristic. Recent research investigates the development of high strength nano-structured aluminum sheet and titanium alloys, as well as their behaviour in roll forming with regard to formability, material behaviour and shape defects. The development of new materials is often limited to small scale samples due to the high preparation costs. In contrast, industrial application needs larger scale tests for validation, especially in roll forming where a minimum sheet length is required to feed the sample trough the roll forming machine. This work describes a novel technique for studying roll forming of a short length of experimental material. DP780 steel strips (500mm – 1300mm length) were welded between two mild steel carrier sheets of similar width and thickness giving an overall strip length of 2m. Roll forming trials were performed and longitudinal edge strain, bow and springback determined on the welded samples and samples formed of full length DP780 strip before and after cut off. The experimental results of this work show that this method gives a reasonable approach for predicting material behavior in roll forming transverse to the rolling direction. In contrast to that significant differences in longitudinal bow were observed between the welded sections and the sections formed of full length DP780 strip; this indicates that the applicability of this method is limited with regard to predicting longitudinal material behavior in roll forming.

The predictive validity of bipolar at-risk (prodromal) criteria in help-seeking adolescents and young adults: a prospective study.

There are no established tools to identify individuals at risk for developing bipolar disorder. We developed a set of ultra-high-risk criteria for bipolar disorder [bipolar at-risk (BAR)]. The primary aim of the present study was to determine the predictive validity of the BAR criteria.

Biomarkers and clinical staging in psychiatry

Personalized medicine is rapidly becoming a reality in today's physical medicine. However, as yet this is largely an aspirational goal in psychiatry, despite significant advances in our understanding of the biochemical, genetic and neurobiological processes underlying major mental disorders. Preventive medicine relies on the availability of predictive tools; in psychiatry we still largely lack these. Furthermore, our current diagnostic systems, with their focus on well-established, largely chronic illness, do not support a pre-emptive, let alone a preventive, approach, since it is during the early stages of a disorder that interventions have the potential to offer the greatest benefit. Here, we present a clinical staging model for severe mental disorders and discuss examples of biological markers that have already undergone some systematic evaluation and that could be integrated into such a framework. The advantage of this model is that it explicitly considers the evolution of psychopathology during the development of a mental illness and emphasizes that progression of illness is by no means inevitable, but can be altered by providing appropriate interventions that target individual modifiable risk and protective factors. The specific goals of therapeutic intervention are therefore broadened to include the prevention of illness onset or progression, and to minimize the risk of harm associated with more complex treatment regimens. The staging model also facilitates the integration of new data on the biological, social and environmental factors that influence mental illness into our clinical and diagnostic infrastructure, which will provide a major step forward in the development of a truly pre-emptive psychiatry.

Performance comparison of abrasion resistant textile motorcycle clothing

 Falling at speed onto a tarmac surface during cycling can cause abrasion and laceration of the skin and body tissue. Motorcycle clothing designed to reduce or avoid this type of injury has traditionally been made of animal leather as it has well known resistance to abrasion. In the last 20 years there has been an emergence of textile clothing reinforced with high performance/tenacity fibres such as those made from polyamides, aramids, ultra high molecular weight polyethylene and liquid crystal. Almost no comparative work has been undertaken to provide insight into the level of protection these clothing layers can provide.
This work has used a CE standard test method to evaluate a number of abrasion resistant textile pant products and compare them with a leather race product. It analysed the protective fabric layer structure for mass, thickness, construction method and resistance to abrasion.
Structures manufactured from high tenacity fibres performed better than those from lower tenacity ones. Fabric construction method and mass per unit area were the two key variables in providing an abrasion protective layer. Structures manufactured from knitted para-aramid fibres performed better than their woven counterparts due to the method of fabric failure. Several well designed protective layers performed at a similar level to that of leather; however, most garments tested failed to meet the lower level European standard of abrasion resistance (CE level 1), which may put their wearer at risk in the advent of a collision.

An analytical approach to predict web-warping and longitudinal strain in flexible roll formed sections of variable width

To reduce weight and improve passenger safety there is an increased need in the automotive industry to use Ultra High Strength Steel (UHSS) for structural and crash components. However, the application of UHSS is restricted by their limited formability and the difficulty of forming them in conventional stamping. An alternative method of manufacturing structural auto body parts from UHSS is the flexible roll forming process, which allows the manufacture of metal sheet with high strength and limited ductility into complex and weight-optimized components. One major problem in the flexible roll forming of UHSS is the web-warping defect, which is the deviation in height of the web area over the length of the profile. It has been shown that web-warping is strongly dependant to the permanent longitudinal strain formed in the flange of the part. Flexible roll forming is a continuous process with many roll stands, which makes numerical analysis extremely time intensive and computationally expensive. An analytical model of web-warping is therefore critical to improve design efficiency during the early process design stage before FEA is applied. This paper establishes for the first time an analytical model for the prediction of web-warping for the flexible roll forming of a section with variable width. The model is based on evaluating longitudinal edge strain in the flange of the part. This information is then used in combination with a simple geometrical model to investigate the relationship between web-warping and longitudinal strain with respect to process parameters.

An improved and fast UHPLC-PDA methodology for determination of L-ascorbic and dehydroascorbic acids in fruits and vegetables: evaluation of degradation rate during storage

This study provides a versatile validated method to determine the total vitamin C content, as the sum of the contents of L-ascorbic acid (L-AA) and dehydroascorbic acid (DHAA), in several fruits and vegetables and its degradability with storage time. Seven horticultural crops from two different origins were analyzed using an ultrahigh-performance liquid chromatographic–photodiode array (UHPLC-PDA) system, equipped with a new trifunctional high strength silica (100% silica particle) analytical column (100 mm×2.1 mm, 1.7 μm particle size) using 0.1% (v/v) formic acid as mobile phase, in isocratic mode. This new stationary phase, specially designed for polar compounds, overcomes the problems normally encountered in HPLC and is suitable for the analysis of large batches of samples without L-AA degradation. In addition, it proves to be an excellent alternative to conventional C18 columns for the determination of L-AA in fruits and vegetables. The method was fully validated in terms of linearity, detection (LOD) and quantification (LOQ) limits, accuracy, and inter/intraday precision. Validation experiments revealed very good recovery rate of 96.6±4.4% for L-AA and 103.1±4.8 % for total vitamin C, good linearity with r2-values >0.999 within the established concentration range, excellent repeatability (0.5%), and reproducibility (1.6%) values. The LOD of the method was 22 ng/mL whereas the LOQ was 67 ng/mL. It was possible to demonstrate that L-AA and DHAA concentrations in the different horticulture products varied oppositely with time of storage not always affecting the total amount of vitamin C during shelf-life. Locally produced fruits have higher concentrations of vitamin C, compared with imported ones, but vegetables showed the opposite trend. Moreover, this UHPLC-PDA methodology proves to be an improved, simple, and fast approach for determining the total content of vitamin C in various food commodities, with high sensitivity, selectivity, and resolving power within 3 min of run analysis.

Determination of lipophilic and hydrophilic antioxidants in Solanum Lycopersicum L. tomato from Gordal variety by LL-USAE combined with UHPLC-PDA/FLR

Tomato (Lycopersicon esculentum L.) is one of the main constituents of the Mediterranean diet. Its consumption has been proposed to reduce the risk of cardiovascular diseases and certain types of cancer. It is therefore one of the most popular and extensively consumed vegetable crop worldwide. To gain insights on the potential of Lycopersicon esculentum L. as bioactive food, two analytical methodologies were developed to determine the levels of the lipophilic -tocopherol, α-tocopherol, β-carotene, lycopene; and hydrophilic antioxidants ascorbic acid. The quantification of total carotenoids (β-carotene and lycopene) was assessed through a liquid–liquid ultrasound assisted extraction (LL-USAE) in combination with ultraviolet-visible spectroscopy (UV-Vis), according to method of mean, for total carotenoids (λmáx = 450 nm. The ultra-high performance liquid chromatographic using both photodiode array and fluorescence detection (UHPLC-PDA/FLR), allows the identification and quantification of the target lipophilic and hydrophilic antioxidants. This methodology UHPLC-PDA/FLR is fast, simple and revealed a high sensitivity for the compounds under study. The limits of detection (LODs) and quantification (LOQs) obtained were much lower (about 10 times) than the reported in literature. The method LL-USAE/UV-Vis was validated and applied to different tomato foodstuffs. The results reveal a small increase of carotenoids content during maturation, reaching the maximum level when ripe. These results complement those obtained by the ORAC and TBARS assays that show an increase of antioxidant capacity during maturation. The LODs ans LOQs obtained were also about 10 times lower than reported in literature. The carotenoid content was also evaluated by LL-USAE/UV-Vis in different tomatoes varieties. Regional variety present the high carotenoid level, followed by campari and gordal, and at last grape. This methodology was also applied to different processed food samples containing tomatoes derivatives. Highest carotenoids content were obtained in concentrated tomato foodstuffs.

Qualidade microbiológica de leite UHT caprino: pesquisa de bactérias dos gêneros Staphylococcus, Bacillus e Clostridium

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Implementação da técnica de difração de elétrons de baixa energia

The purpose of this study is to describe the implementation of the Low Energy Electron Diffaction (LEED) technique in the Laboratory of Magnetic Nanostructures and Semiconductors of the Department of Theoretical and Experimental Physics of the Universidade Federal do Rio Grande do Norte (UFRN), Natal, Brazil. During this work experimental apparatus were implemented for a complete LEED set-up. A new vacuum system was also set up. This was composed of a mechanical pump, turbomolecular pump and ionic pump for ultra-high vacuum and their respective pressure measurement sensors (Pirani gauge for low vacuum measures and the wide range gauge -WRG); ion cannon maintenance, which is basically mini-sputtering, whose function is sample cleaning; and set-up, maintenance and handling of the quadrupole mass spectrometer, whose main purpose is to investigate gas contamination inside the ultra-high vacuum chamber. It should be pointed out that the main contribution of this Master's thesis was the set-up of the sample heating system; that is, a new sample holder. In addition to the function of sample holder and heater, it was necessary to implement the function of sustaining the ultra-high vacuum environment. This set of actions is essential for the complete functioning of the LEED technique