802 research outputs found

    The e!ects of a non-intervention HACCP implementation on process hygiene indicators on bovine and porcine carcasses

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    Four sites on each of 720 dressed carcasses (360 bovine and 360 porcine) were sampled (2,880 samples in total) in a single commercial abattoir slaughtering cattle and pigs using two separate slaughterlines. The carcasses were sampled before HACCP (pre-HACCP; 960 samples) and after HACCP implementation (post-HACCP; 1,920 samples) and Total Viable Count (TVC), Enterobacteriaceae count (EC) and Salmonella spp. prevalence were determined. During the pre-HACCP period, mean TVC levels on four tested sites varied on bovine carcasses between 3.03 and 4.19 log10 cfu/cm2 and on porcine carcasses between 3.73 and 3.99 log10 cfu/cm2. During the post-HACCP period, TVC levels on all tested sites on carcasses were further signicantly reduced, by 0.33-1.64 log and 1.13-2.04 log on bovine and porcine carcasses, respectively, compared to the pre-HACCP period. Both the EC occurrence in samples and EC levels in EC-positive samples somewhat decreased during post-HACCP as compared to pre-HACCP period, but the reductions were not statistically signicant due to large proportion of EC-negative samples and very low counts in EC-positive samples. Salmonella spp. was not detected in any of bovine or porcine carcass samples, regardless of whether they were taken pre- or post-HACCP. Overall, the processhygiene- improving eects of non-intervention HACCP have been proven through reduction of TVC on carcasses, but could not be veried in the present study through similar reductions in EC and/or Salmonella, because of their low levels and/or absence

    New Evidences on Domestication of the Horse (Equus Ferus Caballus) and Origine of Domestic Mountain Pony

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    The results of draft genome research of permafrost horse bone dated approximately 560-780 (kyr BP) have been published recently. According to the data representing the oldest full genome sequence compared to the modern genomes of domesticated horse, Przewalskii and donkey it was suggested that the Equus lineage gave rise to contemporary horses, zebras and donkeys some 4.0 to 4.5 million years ago, twice increasing the assumed time to the common ancestor. Upon the phylogenetic and divergence analyses it was estimated that the Przewalskii and domestic horse populations diverged some 38-72 kyr BP and that there are no evidences that admixtures between Przewalskii and domestic horse populations occurred post-divergently thus Przewalskii’s involvement in the process of horse domestication has been excluded. The new data on ancient equide genome question the conventional theory on the origin of Domestic mountain pony. Upon the protein variability of the Domestic mountain pony the influence of diluvial genome on the population was confirmed and this finding differed from the conventional theory stating E. f. Przewalskii and E. ferus caballus as ancestors of the autochthonous population. The role of different ancestral horses in evolution of our autochthonous population is therefore unclear. The questions emerging from the most recent genetic and proteomic research in concern with the autochthonous populations are presented in the paper

    Study of single-phase convection and condensation in thermoplate heat exchanger (part I)

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    Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.The heat transfer and pressure drop in a thermoplate heat exchanger operated as condenser have been investigated experimentally. In order to separate the heat transfer resistances in the condensation process, first the single phase forced convection in the thermoplate using distilled water and Marlotherm oil has been studied and correlation for the Nusselt number and friction factor developed. For the condensation experiments an apparatus has been conceived comprising two identical condensers made of the same thermoplate type as employed in the single phase experiments. Isopropanol was used as test fluid at pressures below the atmospheric pressure. With the aid of the results obtained in the single phase studies the heat transfer resistances in the condensation experiments were separated and expressions for the condensation heat transfer and pressure drop developed.cs201

    Chemical composition of chicken meat produced in extensive indoor and free range rearing systems

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    The present study involves the analysis of the chemical composition of white meat (breast muscles) and dark meat (leg muscles) of broilers in extensive indoor and free range systems. The length of fattening period was 56 days. At 56 days of age, 6 male and 6 female broilers were randomly selected from each rearing system and slaughtered. Cooled carcasses were dissected into primal cuts. Breast and leg muscle (thigh and drumstick) samples were used for chemical analyses. The obtained resultssuggested that free range rearing system was more favourable than extensive indoor system, as it resulted in a significantly higher protein content and a lower fat content of white and dark chicken meat. Female broilers produced a higher fat content and a somewhat lower protein content as compared to males.Keywords: Chemical composition, chicken meat, rearing system, se

    Reparatory and Manufacturing Hard-Facing of Working Parts Made of Stainless Steels in Confectionary Industry

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    In this paper, for the sake of improving the reparatory hard-facing technology is especially analyzed reparatory hard-facing of tools for manufacturing compressed products in confectionary industry. Those products are being made of a mixture consisting of several powdery components, which is compressed under high pressure. In that way the connection between particles is realized, thus achieving certain hardness and strength of the confectionary product. The considered tool is made of high-alloyed stainless steel. The tool contains 30 identical working places. Besides the production process wear, on those tools, from time to time, appear mechanical damage on some of the products' shape punches, as cracks at the edges, where the products' final shapes are formed. Those damages are small, size wise, but they cause strong effect on the products' final shape. The aggravating circumstance is that the shape punch is extremely loaded in pressure, thus after the reparatory hard-facing, the additional heat treatment is necessary. Mechanical properties in the heat affected zone (HAZ) are being leveled by annealing and what also partially reduces the residual internal stresses

    Study of single-phase convection and condensation in thermoplate heat exchanger (part II)

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    Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.The heat transfer and pressure drop in a thermoplate heat exchanger operated as condenser have been investigated experimentally. In order to separate the heat transfer resistances in the condensation process, first the single phase forced convection in the thermoplate using distilled water and Marlotherm oil has been studied and correlation for the Nusselt number and friction factor developed. For the condensation experiments an apparatus has been conceived comprising two identical condensers made of the same thermoplate type as employed in the single phase experiments. Isopropanol was used as test fluid at pressures below the atmospheric pressure. With the aid of the results obtained in the single phase studies the heat transfer resistances in the condensation experiments were separated and expressions for the condensation heat transfer and pressure drop developed.cs201

    Reduction of thermal conductivity in phononic nanomesh structures

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    Controlling the thermal conductivity of a material independently of its electrical conductivity continues to be a goal for researchers working on thermoelectric materials for use in energy applications and in the cooling of integrated circuits. In principle, the thermal conductivity Îș and the electrical conductivity σ may be independently optimized in semiconducting nanostructures because different length scales are associated with phonons (which carry heat) and electric charges (which carry current). Phonons are scattered at surfaces and interfaces, so Îș generally decreases as the surface-to-volume ratio increases. In contrast, σ is less sensitive to a decrease in nanostructure size, although at sufficiently small sizes it will degrade through the scattering of charge carriers at interfaces. Here, we demonstrate an approach to independently controlling Îș based on altering the phonon band structure of a semiconductor thin film through the formation of a phononic nanomesh film. These films are patterned with periodic spacings that are comparable to, or shorter than, the phonon mean free path. The nanomesh structure exhibits a substantially lower thermal conductivity than an equivalently prepared array of silicon nanowires, even though this array has a significantly higher surface-to-volume ratio. Bulk-like electrical conductivity is preserved. We suggest that this development is a step towards a coherent mechanism for lowering thermal conductivity

    Independent Assessment of the 2018–19 fish deaths in the lower Darling

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    Three significant fish death events occurred in the Darling River near Menindee between December 2018 and January 2019. The three events took place within two adjacent weir pools in a 30 km reach of river between Texas Downs Station and Weir 32 (DPI NSW Fisheries, 2019). The main native fish species involved included Murray Cod, Silver Perch, Golden Perch, Bony Herring, with mortality estimates in the range of hundreds of thousands to over a million fish. Though post-event fish population sampling is yet to be conducted, we expect that these mortalities will impact populations in the lower Darling River, and perhaps beyond, for many years. These events constitute a serious ecological shock to the lower Darling and reverse positive ecological outcomes that had accrued from environmental watering programs. We have determined that fish deaths events were primarily caused by local hydrological and climatic conditions (Figure 1-1). The extreme hot and dry climate during 2018, extending into 2019, shaped the conditions that saw a large fish biomass, which had flourished since favourable spawning conditions in 2016, isolated in the weir pools around Menindee, with no means of escaping upstream or downstream. Those adverse climate conditions also shaped the subsequent algal bloom development and the strong and persistent thermal stratification of the weir pools, which created hypoxic conditions in the bottom waters of the pools. All that was needed for this to have a fatal impact on the fish was a trigger for the weir pool waters to become destratified and deprive the fish of oxygen. That trigger duly arrived with a series of sudden cool changes in the weather, with temperature drops and wind action initiating the turnover of the weir pool waters. This sudden depletion of oxygen, combined with the already high water and air temperatures, would have offered the large biomass of stressed fish no means of escape. For each fish death event, the weir pool in which the fish were trapped was bordered downstream by an impenetrable barrier (a weir) and upstream by a dry channel. Ultimately, it was the rapid transition from very favourable conditions to very adverse ones that resulted in such high numbers of fish deaths. We have also determined that the fish death events were shaped by a broader climatic, hydrologic and basin management context that placed the lower Darling River at risk of such fish deaths. The preceding six years (since 2012) had seen two high flow events that had delivered water into Menindee Lakes (2012 and 2016) and offered opportunities for substantial fish breeding and recruitment. Fish populations were further enhanced by the judicious use of environmental water. The end result was a considerable biomass of fish within the Menindee Lakes, post 2016. Outside of these high flow events there were minimal flows in the Darling River below Bourke. This period was preceded by the Millennium drought (2000-2010), during which time flows across the entire northern Murray– Darling Basin were reduced. All of the hydroclimatic evidence available indicates that the years since 2000 have been some of the driest on record, in terms of inflows into major upstream storages, combined with an increased number of extreme heat days, which would have had a major impact on water quality in remnant pools. Soon after the events, Basin government officials met and developed an action plan to respond to the crisis. Immediate actions underway include additional water quality monitoring in the lower Darling, the use of aerators and targeted fish relocations. These immediate actions are welcomed, however, the current situation remains critical – without significant inflows, further deaths of surviving fish may be expected. We consider that priorities and actions in the short-term should focus on anticipating a repeat of ‘worst-case scenario’ outcomes with responses focussed at the site scale. In addition, the Minister for Agriculture and Water Resources announced a Native Fish Management and Recovery Strategy to help manage and recover fish populations across the Basin. We consider that this provides a good opportunity to enhance native fish management and support native fish population recovery and should be developed and implemented through a genuine collaboration between governments, communities, and Traditional Owners. The strategy needs to build on existing and lapsed native fish programs across the Basin. Through our investigations, it became evident to us that, over the long-term, the extant water access arrangements in the northern Basin, as well as limitations in the river models used to plan water sharing, place the lower Darling River at a higher risk of conditions that can lead to fish deaths during droughts than has previously been anticipated. Given that we are witnessing an increasing frequency of low inflow sequences in the northern Basin, this presents a serious problem for safeguarding fish populations, and populations of other resident biota, during drought in the lower Darling. We have identified that changes to Barwon–Darling water access arrangements made by NSW just prior to the commencement of the Basin Plan in 2012 have enhanced the ability of irrigators to access water during low flow periods and during the first flow event immediately after a cease-to-flow period. Further, it appears that the river models used to develop water sharing arrangements have a tendency to overestimate streamflows during dry sequences, and hence underestimate the impacts of extractions during dry times
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