The Effects of Stress on Physiology and Meat Quality in Cultured Channel Catfish

Stress during fish culture can impact growth, physiology and fillet quality. Maintenance of high quality seafood is important to ensure the production of a highly marketable product. The present study assessed how sequential stressors affect the physical, physiological, sensory and quality characteristics of channel catfish (Ictalurus punctatus) fillets. Temperature (25°C or 33°C) and dissolved oxygen (DO, ~2 mg/L or \u3e5 mg/L) were maintained for four weeks, followed by socking and transport stress for a total of 12 treatments. After each stage of stress (environment, socking and transport), physical (length, weight and feed consumption), physiological (hematocrit, plasma cortisol, pH, glucose, lactate, total protein, osmolality and ionic composition) and fillet quality (color, texture, sensory and pathogen load) attributes of the fish and fillets were evaluated. Fillet yield decreased with increasing severity of environmental stress. Overall, increasing stress resulted in decreased feed consumption, growth and fillet yields. A cumulative stress response was identified with regard to circulating cortisol and glucose, which increased with each sequential stress event. Under low oxygen conditions there was a suppression of the stress response. Handling imposed a more pronounced physiological response than environmental conditions. The sequential stressors resulted in a less intensely colored fillet that was less red, which suggests the quality changes imposed are beneficial to the marketability of the fillets. However, increased redness in fish reared under high temperatures and oxygen levels suggest that an increased prevalence of red fillets can be expected. Sensory analysis revealed that fillet flavor was acceptable in all treatments with the severe stress treatment preferred due to lower intensity of less favorable flavor attributes. The changes in flavor were presumably due to fasting of the stressed fish and a subsequent purging of fat stores. As fish progressed through the harvest event, cook loss decreased, tenderness increased and pH increased, indicating that stress induced positive textural changes. Proteomic analysis revealed mainly down-regulation of structural and metabolic proteins, which indicates higher proteolytic activity and an adjustment in energy metabolism in response to stress. The overall effects of chronic environmental conditions and handling highlight the importance of managing for stress in cultured channel catfish

Technical and Economic Criteria to Select Pavement Surfaces of Port Handling Plants

A port is an intermodal system in which many logistics activities requiring properly constructed areas occur. The large extension of these areas poses a major problem in choosing materials with technical and economic implications. Choice and design of pavements are directly related to the port handling systems and procedures for the disposal of the cargo units. The paper presents the design and verification procedures for three equivalent pavements for a handling pavement in an Italian medium-sized port trafficked by reach stackers moving containers. An asphalt pavement, a concrete pavement, and a concrete block pavement have been considered during the 20-year service life. Empirical and analytical methods have been adopted to design and verify the pavements. The structures have been examined in terms of economic concerns during the overall service life, considering both construction and maintenance costs, in order to determine the most cost-effective option. The results demonstrate the inappropriateness of asphalt pavement, in the examined case, from a construction costs point of view. Furthermore, the overall discounted costs show an inversion of convenience between block concrete pavement and cast in situ concrete: the latter is the cheaper solution. The proposed methodology can balance often conflicting objectives in matters of durability and funds management, providing answers to a complex topic

Low stress and safe handling of outdoor cattle - effective measures to improve work environment and avoid dangerous situations

Grazing cattle are needed to preserve 450 000 hectares of semi-natural grasslands of high biodiversity in Sweden. Keeping cattle outdoors promotes their health and possibili¬ties to conduct natural behaviors. Working with cattle on pasture however, can increase accident rates (Health and Safety Authority, 2011). During the last two years, five fatali¬ties and several accidents have occurred during handling of cattle in Sweden. A method, based on knowledge of the animals’ natural behavior, referred to as low stress stock han¬dling (LSS-method), has been introduced to Sweden for cattle handling (Atkinson, 2011). A handler who consistently uses this method prevents the use of hits, sticks, harsh voice or negative forceful handling techniques. A consistent predictable approach from the han¬dler creates consistent and predictable animal behavior in return. Cattle become more trusting with their handlers and consequently more cooperative. This positive interaction between human being and animal can lead to both a safer work situation and a better animal welfare. On two of five studied farms so far, the LSS-method was actually inter¬vened during the observations, resulted in a successful reversal of conflict behaviour. On farm1, a highly stressed heifer took over three hours in attempt to load into a transport. It was successfully loaded within an hour after the intervention. On another farm, five escaped cows that the farmer had attempted to capture unsuccessfully for three conse¬cutive weeks were successfully captured through using the LSS-method

Logistic regression for simulating damage occurrence on a fruit grading line

Many factors influence the incidence of mechanical damage in fruit handled on a grading line. This makes it difficult to address damage estimation from an analytical point of view. During fruit transfer from one element of a grading line to another, damage occurs as a combined effect of machinery roughness and the intrinsic susceptibility of fruit. This paper describes a method to estimate bruise probability by means of logistic regression, using data yielded by specific laboratory tests. Model accuracy was measured via the statistical significance of its parameters and its classification ability. The prediction model was then linked to a simulation model through which impacts and load levels, similar to those of real grading lines, could be generated. The simulation output sample size was determined to yield reliable estimations. The process makes it possible to derive a suitable line design and the type of fruit that should be handled to maintain bruise levels within European Union (EU) Standards. A real example with peaches was carried out with the aid of the software implementation SIMLIN®, developed by the authors and registered by Madrid Technical University. This kind of tool has been demanded by inter-professional associations and grading lines designers in recent year

Numerical analysis of structural behavior of welded wire reinforcement in reinforced concrete beams

Thesis (M.S.) University of Alaska Fairbanks, 2016Modernization and industrialization have paved the way for the construction industry of India to expand. On the other hand the Indian construction industry is set to face an acute workforce shortage. The shortage of construction workers has in fact slowed down the growth of this industry in major cities across the country and escalated its cost by 40 percent. An alternative way to replace the labor force is by automation techniques. This study is a numerical analysis to evaluate structural behavior of simply supported concrete beams reinforced with welded wires in comparison with mild steel reinforced concrete beams. Welding conventional steel bars (60 ksi) reduces their shear strength by 50 percent. Welded Wire Reinforcement (80 ksi), with its greater strength, higher durability, significantly lower placing and overall cost, provides an alternative and perhaps a better substitution for mild steel bars. The commercial finite element analysis program, ABAQUS, was used to model the non-linear behavior of reinforced concrete beams. In order to evaluate the structural behavior of welded wire reinforced concrete beams, different configurations of longitudinal and transverse wires have been considered. First, different types of stirrup configurations in a rectangular reinforced concrete beam are compared with a conventional reinforced beam. Second, a structurally performing welded wire configuration is compared with a Mexican chair styled reinforcement configuration. This part of the analysis is evaluated for a T–beam, used for building roof applications.Chapter 1 Introduction -- Welded Wire Reinforcement -- Traditional Rebar versus Welded Wire Reinforcement (WWR) -- Potential Gains through Welded Wire Reinforcement (WWR) -- Welded Wire Reinforcement Specifications and Nomenclature -- Welded Wire Reinforcement Manufacturing, Handling and Placing -- Aim and Scope -- Outline of Thesis -- Chapter 2 Literature Review -- Impact of Welded Wire Reinforcement in Structural Members -- Welded Wire Reinforcements in Columns -- Welded Wire Reinforcements in Beams and Girders -- Welded Wire Reinforcements in Structural Walls -- Summary -- Chapter 3 Finite Element Modeling of Reinforced Concrete Beams -- ABAQUS Modeling -- Non-linear Behavior of Concrete -- Uniaxial and Biaxial Behavior -- Non-linear Modeling of Reinforced Concrete Beam -- Material Model Properties -- Concrete Damage Plasticity Parameters -- Reinforcement Properties -- Convergence Analysis -- Chapter 4 Numerical Analysis of Concrete Beams Reinforced with Traditional and Welded Wire Reinforcement -- Introduction -- Initial Validation and Mesh Convergence -- Analysis of Welded Wire Reinforcement Grids in Reinforced Concrete Beams -- Rectangular Reinforced Concrete Beams Subjected to Four Point Loading Condition -- Rectangular Reinforced Concrete Beams Subjected to Uniformly Distributed Loading Condition -- T - Beams Subjected to Four Point Loading Condition -- Chapter 5 Conclusion and Recommendation -- Conclusion -- Recommendation -- References

Fatigue analysis-based numerical design of stamping tools made of cast iron

This work concerns stress and fatigue analysis of stamping tools made of cast iron with an essentially pearlitic matrix and containing foundry defects. Our approach consists at first, in coupling the stamping numerical processing simulations and structure analysis in order to improve the tool stiffness geometry for minimizing the stress state and optimizing their fatigue lifetime. The method consists in simulating the stamping process by considering the tool as a perfect rigid body. The estimated contact pressure is then used as boundary condition for FEM structure loading analysis of the tool. The result of this analysis is compared with the critical stress limit depending on the automotive model. The acceptance of this test allows calculating the fatigue lifetime of the critical zone by using the S–N curve of corresponding load ratio. If the prescribed tool life requirements are not satisfied, then the critical region of the tool is redesigned and the whole simulation procedures are reactivated. This method is applied for a cast iron EN-GJS-600-3. The stress-failure (S–N) curves for this material is determined at room temperature under push pull loading with different load ratios R0σmin/σmax0−2, R0−1 and R00.1. The effects of the foundry defects are determined by SEM observations of crack initiation sites. Their presence in tested specimens is associated with a reduction of fatigue lifetime by a factor of 2. However, the effect of the load ratio is more important

Effect of previous handling experiences on responses of dairy calves to routine husbandry procedures

The nature of human–animal interactions is an important factor contributing to animal welfare and productivity. Reducing stress during routine husbandry procedures is likely to improve animal welfare. We examined how the type of early handling of calves affected responses to two common husbandry procedures, ear-tagging and disbudding. Forty Holstein–Friesian calves (n = 20/treatment) were exposed to one of two handling treatments daily from 1 to 5 weeks of age: (1) positive (n = 20), involving gentle handling (soft voices, slow movements, patting), and (2) negative (n = 20), involving rough handling (rough voices, rapid movements, pushing). Heart rate (HR), respiration rate (RR) and behaviour (activity, tail flicking) were measured before and after ear-tagging and disbudding (2 days apart). Cortisol was measured at −20 (baseline), 20 and 40 min relative to disbudding time. There were no significant treatment differences in HR, RR or behaviour in response to either procedure. However, the following changes occurred across both treatment groups. HR increased after disbudding (by 14.7 ± 4.0 and 18.6 ± 3.8 bpm, positive and negative, respectively; mean ± s.e.m.) and ear-tagging (by 8.7 ± 3.1 and 10.3 ± 3.0 bpm, positive and negative, respectively). After disbudding, there was an increase in RR (by 8.2 ± 3.4 and 9.3 ± 3.4 breaths/min, positive and negative, respectively), overall activity (by 9.4 ± 1.2 and 9.9 ± 1.3 frequency/min, positive and negative, respectively) and tail flicking (by 13.2 ± 2.8 and 11.2 ± 3.0 frequency/min, positive and negative, respectively), and cortisol increased from baseline at 20 min post procedure (by 10.3 ± 1.1 and 12.3 ± 1.1 nmol/l positive and negative, respectively). Although we recorded significant changes in calf responses during ear-tagging and disbudding, the type of prior handling had no effect on responses. The effects of handling may have been overridden by the degree of pain and/or stress associated with the procedures. Further research is warranted to understand the welfare impact and interaction between previous handling and responses to husbandry procedures

Development of raised access floor panel by optimisation techniques

Raised access floor panels currently have a chipboard core and are encapsulated within thin layer of galvanised steel. Two key problems with these raised access floor panels are that they are heavy because of the chipboard and expensive, as the cost of steel has increased significantly over the past few years. The consequence of the raised access floor panel’s mass is that they are difficult to handle, they are expensive to transport and they add considerably to the load on a structures foundation. Glass fibre filled epoxy of floor panels were designed and optimised to achieve lighter weights without compromising their strength using Altair Hypermesh software. A material weight reduction of the glass fibre filled epoxy floor panel was achieved by optimised design of the panes using an evolutionary structural optimisation (ESO) method and the introduction of panel ribs. The lighter weight of new raised floors panel would have a significant impact on the loadings of buildings foundation and allow architects to reduce the carbon footprint of a building resulting in reduced construction costs. In addition, a reduction in the weight of the new raised access floor panels would reduce the transportation costs of the panels