Fatigue behaviour of welded joints with cracks, repaired by hammer peening

Rehabilitation of a welded structure, which involves repair of cracked joints, is achieved when the local treatment for repair gives a fatigue strength in the joint equal or above the fatigue strength of the uncracked original detail. If the treatment is properly applied the rehabilitation of the detail is assured, and the nature of the weld toe improvement methods can produce a joint, after repair, with a fatigue strength and residual life greater than the initial detail. The paper presents the results obtained on a fatigue study on the rehabilitation of non‐load carrying fillet welded joints loaded in bending at the main plate and with fatigue cracking at the weld toes of the attachment in the main plate and though the plate thickness. Residual stresses were measured at the surface, with X‐ray diffraction. The residual stresses induced by hammer peening at the weld toe were found to be greater along the longitudinal direction of the plate than in the transverse direction. The peak residual stresses near the weld toe were found to be close to yield in compression, justifying the great benefit of hammer peening. Results of a derived gain factor, g, in fatigue life were obtained as a function of the crack depth repaired by hammer peening.     

Kinetic Parameters for Thermal Degradation of Green Asparagus Texture by Unsteady-state Method

An unsteady-state method was developed for estimating texture degradation during heating-cooling of green asparagus spears. The method used a mathematical model of heat transmission for time-temperature history estimation, and a nonlinear regression of texture measurements of asparagus spears to estimate kinetic parameters. The specific heat, conductivity and convective coefficient of green asparagus were determined experimentally and used in the mathematical model for temperature estimation. Values obtained were Ea = 76.19±0.13 kJ/mol and k_1158°C= 0.00528±0.00005 s^-1. Good agreement was found between predicted and observed texture values. The method was compared with the classical steady-state method. The mathematical model and kinetic parameters estimated could be used to design and evaluate thermal processes for green asparagus.     

Surface active molecules: preparation and properties of long chain nα-acyl-l-α-amino-ω-guanidine alkyl acid derivatives

A new route for the synthesis of long chain N ^α-acyl- l -α-amino-ω-guamdine alkyl acid derivatives, with cationic or amphoteric character has been established. The general formula of these compounds is shown below.
A physico-chemical and antimicrobial study of these products as a function of the alkyl ester or sodium salt (R), the straight chain length of the fatty acid residue ( x ) and the number of carbons between the ω-guanidine and ω -carboxyl group ( n ) has been investigated.
The water solubility, surface tension, critical micelle concentration (c.m.c.) and minimum inhibitory concentration (MIC) against Gram-positive and Gram-negative bacteria (including Pseudomonas) has been determined.
Dicyclohexylcarbodiimide has been used to condense fatty acids and α -amino-ω-guanidine alkyl acids. In these conditions protection of the ω-guanidine group is not necessary. The main characteristic of this synthetic procedure is the use of very mild experimental conditions (temperature, pH) to form the amide linkage which leads to pure optical compounds in high yield in the absence of electrolytes.
The results show that some structural modifications, particularly the protection of the carboxyl group, promote variations of the surfactant and antimicrobial properties. Only those molecules with the blocked carboxyl group (cationic molecules, where R = Me, Et or Pr) showed a good surfactant and antimicrobial activity. When the carboxyl group was unprotected (amphoteric molecules, where R = Na⁺) the resulting compounds were inactive.     

Consumer acceptability and purchase intent of probiotic yoghurt with added glucose oxidase using sensometrics,artificial neural networks and logistic regression

This research aimed to identify the drivers of acceptance and purchase intent of a probiotic (Bifidobacterium longum BL05) nonflavoured yoghurt supplemented with glucose oxidase, and to model the consumers’ acceptability using sensometrics and artificial neural networks (ANN). Consumers (n = 100) evaluated the degree of liking of yoghurt assays in respect of appearance, aroma, taste, texture and overall linking. Sensometric techniques – multiple linear regression (MLR), partial least squares regression (PLS), principal component regression (PCR) – and ANN were used to model the overall liking. Sensory drivers of global acceptance and purchase intent were also determined using logistic regression (LR). Hierarchical cluster analysis (HCA) identified three consumer segments that presented differences in all sensory attributes evaluated (P < 0.05). The ANN model showed the best performance to predict overall liking, followed by the MLR, PLS and PCR, indicating that taste and texture were the most significant attributes impacting the yoghurts overall liking. In accordance with the logistic models, overall acceptance and purchase intent could be predicted with 81.94 and 85.49% accuracy, respectively. The logistic regression indicated that taste was the attribute that contributed significantly (P < 0.0001) to higher scores for purchase intent and was considered the driver of acceptance.     

Cryopreservation of <i>Cyrtopodium hatschbachii</i> Pabst (Orchidaceae) immature seeds by encapsulation-dehydration

The aim of the present study was to investigate the efficiency of the encapsulation-dehydration technique for cryopreservation of Cyrtopodium hastchbachii Pabst seeds. Immature seeds of this species were cryopreserved by an encapsulation-dehydration technique. Seeds of five immature pods, 120 days after pollination, were encapsulated in 3% calcium alginate matrix and pretreated in liquid medium supplemented with 0.08 M sucrose (24 h), 0.15 M sucrose (24 h), 0.25 M sucrose (48 h), 0.5 M sucrose (24 h) and 0.75 M sucrose (24 h) in shaker at 60 rpm. Alginate beads were dehydrated 5 h in silicagel and immersed in liquid nitrogen for 12 h. Cryopreserved beads were thawed at 30°C for 1 min, rehydrated using the same liquid mediums [0.75 M sucrose (24 h), 0.5 M sucrose (24 h), 0.25 M sucrose (48 h) and 0.15 M sucrose (24 h)] and cultivated in half strength Murashige & Skoog medium (1962) with the addition of 2 g/L activated charcoal. Sixty four percent of seeds survived and developed into acclimatized plants after being cryopreserved. In this work, the encapsulation-dehydration technique was employed for first time in Cyrtopodium hatschbachii.     

A cooperative framework for integrating ontologies

Nowadays, there are systems and frameworks that support Ontology construction processes. However, ontology integration processes have not sufficiently been specified to date. In this article, by making use of a cooperative philosophy, we describe a real framework for the integration of ontologies supplied by a predetermined set of (expert) users, who may be interconnected through a communication network. This framework is based on a set of well-defined assumptions that guarantee the consistency of the ontology derived from the ontology integration process. Moreover, in the approach presented here, every (expert) user may consult the so-derived ontology constructed until a given moment in order to refine his or her private ontology. In addition to this, the model proposed in this work allows the experts involved in the construction of the ontology to use their own terminology when querying the global ontology obtained until a given instant from their own co-operative work. The validation of the framework is also included in this work.     

Pilot Study of Cucumber Fermentation: Diffusing Gases and Bloater Damage

A pilot study was made of the effect of temperature (17 and 26°C) and purging, with nitrogen (5-20 L/hr applied continuously and intermittently) or air (20 L/hr for 7 hr/day), o n the development of fermentation and on the incidence of bloater damage in cucumbers. Temperature affected the rate of fermentation and both temperature and purging strongly affected the incidence of bloater damage. At 17°C purging was not necessary, and at 26°C 10 L/hr was sufficient, applied for 7 hr/day for 7 days.     

Determination of a process time for a new product: canned low acid artichoke hearts

In order to obtain a process time for canned low acid artichoke hearts, the heat resistance of Clostridium sporogenes PA 3679 in phosphate buffer (pH 7) and in artichoke puree (pH 5.2) was determined in the range of 100–118°C. D _T values in artichoke puree were determined by the most probable number and plate count methods. D _121°C values were deduced by extrapolation of the curves. An F 8.3/121 (see nomenclature section) target value of 1.8 min, equivalent to an F ₀= 2.5 min, was established considering a D _121°C value of 0.36 min for artichoke puree. The cold point for canned artichoke hearts in 1/2 kg (71.5x117 mm) cans was determined, a set of heat penetration and cooling curves were obtained and the values of the parameters ' j ' and ' f ' were found. A process time was deduced, 21.5 and 23 min of heating at 121°C, following the methods of Patashnik (1954) and Hayakawa (1970, 1974) respectively, in order to reach the F ₀ target of 2.5 min for this new canned food. This process was adequate, as the inoculated experimental pack test showed no altered cans out of 50 inoculated after 21.5 min of heating at 121°C.     

Influence of Brining and Packing Conditions on Product Quality of Capers

The effects of brine concentration (5.7.10.15 and 20% NaCl) on pre-treatment of capers to improve preservation and packing conditions (3–10% salt, 0–1.5% acetic acid and pasteurization) on product stability were studied. All brines containing 10% salt and higher proved equally adequate for the preservation of capers at least for 27 months. The finished products manufactured from stock held in such brines had typical texture flavor and color. The use of lower concentration brines led to off-flavor development and softening of the product. Pasteurization (80°C, 15 min) of the finished product proved efficient for preventing spoilage. Non-pasteurized samples required high salt (ca 6%) and acid (ca 1%) levels for preservation. Otherwise, a yellow sediment developed as a consequence of microbial growth.