Shelf Life and Quality Attributes Of Fresh Beef Infused With Organic Acids.

Fresh beef is a highly perishable food. It has a shelf life of one day at ambient temperature and a few days at refrigerated temperature. This study was conducted with the objective of extending the shelf life of fresh beef by infusing organic acids such as citric, tartaric, acetic and lactic acids, and combination of the organic acids with sodium chloride. Fresh beef (longissmus do@ purchased from the local market were sliced and were infused with citric, acetic, lactic and tartaric acids in concentration of 0.5%, 0.75% and 1 %, and combination of 1.00% of citric and acetic acids with and without sodium chloride by placing samples in vacuum desiccators and pulling the vacuum to 29.5 in. Hg. for 20 min.,. All samples were packed in vacuum packs (22 (L) x 18 (w) crn. and stored at S°C for 28 days. pH, A, Total Plate Count (TPC), Thiobarbaturic acid values, Hunter colour values , instrumental texture, proximate composition were determined. The pH values of treated samples dropped from the initial pH of 5.30 (untreated) to 4. 20 - 4. 47 and upon storage, the pH values of all sampies increased gradually. The TPC values were lower than 10' CFUlg on day 16, 20 and 28 in samples treated with 0.5%, 0.75% and 1.00% acids, respectively. The proximate com p s iti on of treated samples was affected by infusion process. The instrumental texture of fresh beef was harder upon treatment. The maximum shelf life of treated beef was 12 - 24 days for samples treated with 0.5% of all acids, 16 - 24 days for samples treated with 0.75% and 20 - 28 for samples treated with 1.00%. Citric acid in concentration of 1.00% gave the best effect which was followed by acetic acid. In citric and acetic acids and citric and acetic acids with sodium chloride combinations, the later in the ratio of 2:1 was more effective in decreasing the initial pH of fresh beef immediately after infusion. Increasing concentration of NaCl in the infusion solution resulted in the smaller decrease in the pH values. The TPC value was observed in samples treated with 2:1 citric: acetic acids. The growth of S.aureus and E.coli 0157:H7 were significantly (B0.05) decreased by 0.85 loglo and 0.73 logto, respectively. The initial thiobarbituric acid value in untreated fresh beef was 0.735 mg MDNkg which significantly (pc 0.05) decreased in all treated samples. At the end of storage study, lowest TBA values were obtained in samples treated with 2:l citric and acetic. The increase in the addition of NaCl caused a parallel increased in TBA values. For colour, Hunter 'b' and 'L' values increased with storage time while 'a' decreased significantly (R0.05). The processed beef burger during chilled storage had a storage life of 8 days

Development and characterization of Sulfur dioxide gas analyzer

Sulfur dioxide (SO2) is considered one of the main contaminants in air because of its major contribution to acid rain and due to the major health concerns associated with exposure to high concentrations of SO2. Hence, there has been a great interest in the determination of SO2 because of continuous monitoring its impacts on the environment and public health. However, limited reports targeted SO2 in gas streams. Therefore, the primary objective of the present work was to develop affordable gas analyzer for continuous monitoring of SO2 in gas streams. The principle of operation of the described analyzer was based on a gas diffusion scrubber (in the form of hollow fiber membrane module, HFMM) as a prior gas sampling unit which allowed the contact between the gas stream and a selected carrier solution. SO2, present in the gas stream diffuses to and dissolves in the flowing carrier solution. The concomitant changes of the carrier solution can be measured by means of a suitable flow-through detector placed downstream to produce analytical signal for the quantification of SO2 in the gas stream. The selected detectors were limited to electrochemical detectors because of their simplicity and they do not usually require additional reagents or prior derivatization reactions. With regards to the chemical properties of SO2, pH, conductivity and amperometric detectors were selected as potential detectors for the construction of SO2 gas analyzers. The first detector evaluated in the current project was based on potentiometric pH measurements. The obtained optimum experimental conditions for S02 detection were 0.1 M potassium oxalate buffer as carrier solution at flow rate 1.5 mL/min, gas flow rate 250 mL/min, using flat-bottom pH glass electrode and HFMM consisting of 60 PP fibers. Under the optimized conditions, a Nernestian slope up to 10000 ppm with a detection limit of 1.0 ppm SO2 was obtained. The response time varied from 20 to 200 seconds whereas the recovery time was 600 seconds when SO2 concentration decreased from 1000 ppm to zero. The pH-detector showed excellent selectivity. CO2 up to 500 folds did not exert significant interference and H2S up to 5 folds greater than that of SO2 was tolerated. The second described detector was based on conductivity detection. The obtained optimum experimental conditions for S02 detection were 1.0 mM H2O2 as carrier solution at flow rate 2.0 mL/min, gas flow rate 200 mL/min, using commercial conductivity probe and HFMM consisting of 60 PP fibers. The favorable performance characteristics of the proposed SO2 analyzer was successfully applied in monitoring real experiment of removing SO2 from a gas stream. The optimized detector gave linear range up to 2500 ppm, a detection limit of 16 ppm for SO2 in nitrogen and 115 to 180 seconds for recovery time. In addition the conductometric detector showed no interference of CO2 up to 100 folds greater than that of SO2. The third detector was based on a novel amperometric detection. The utilized electrode was based on an organic conducting salt (OCS) based on tetrathiafulvalenetetracyanoquinodimethane [TTF-TCNQ] complex. The TTF-TCNQ was mixed with silicone oil in 1:1.25 ratio. The formed paste was packed in Teflon cavity (12 mm in diameter). The obtained optimum experimental conditions for SO2 detection were 0.2 M potassium phosphate buffer pH 6.5 as carrier buffer at flow rate 5.0 mL/min, using commercial HFMM mini-module. The TTF-TCNQ electrode was polarized at 0.24 V vs. SCE. The obtained amperometric response was linear up to 500 ppm and can detect as small as 10 ppm of SO2 and showed no interference at very high levels of CO2 (3900 folds). The advantages of the developed SO2 gas analyzers were manifold which include (i) the obtained performance characteristics of the described SO2 analyzer can be tuned for certain application requirements such as high sensitivity, wide linearity range, high selectivity towards a particular interfering gas, etc. (ii) low construction and operational cost, (iii) no special disposal required for the waste carrier, (iv) favorable response characteristics such as fast response, excellent reproducibility and signal stability, (v) the entire analyzer construction can be miniaturized to provide low-cost portable unit for industrial and/or environmental monitoring. This latter advantage presents some potential for commercialization of the described analyzer

Unconventional TV Detection using Mobile Devices

Recent studies show that the TV viewing experience is changing giving the rise of trends like "multi-screen viewing" and "connected viewers". These trends describe TV viewers that use mobile devices (e.g. tablets and smart phones) while watching TV. In this paper, we exploit the context information available from the ubiquitous mobile devices to detect the presence of TVs and track the media being viewed. Our approach leverages the array of sensors available in modern mobile devices, e.g. cameras and microphones, to detect the location of TV sets, their state (ON or OFF), and the channels they are currently tuned to. We present the feasibility of the proposed sensing technique using our implementation on Android phones with different realistic scenarios. Our results show that in a controlled environment a detection accuracy of 0.978 F-measure could be achieved.Comment: 4 pages, 14 figure

MODEL-BASED DIAGNOSTICS OF SIMULTANEOUS TOOTH CRACKS IN SPUR GEARS

This study aims at developing a numerical model that could be used to simulate the effect of tooth cracks on the vibration behavior of spur gears. Gears are a key component that is widely used in various rotating equipment in order to transmit power and change speed. Any failure of this vital component may cause severe disturbance to production and incur heavy financial losses. The tooth fatigue crack is amongst the most common causes of gear failure. Early detection of tooth cracks is crucial for effective condition-based monitoring and decision making. The scope of this work was widened to include the influence of multiple simultaneous tooth cracks on the time and frequency domain responses at various locations and with different severity levels. As cracks significantly alter the gear mesh stiffness, a finite element analysis was performed to determine the stiffness variation with respect to the angular position for different combinations of crack lengths. A simplified six degrees of freedom nonlinear lumped parameter model of a one-stage gearbox was developed to simulate the vibration response of faulty spur gears with the consideration of inter-tooth friction. Four different multiple crack scenarios were proposed and studied. The performances of various statistical fault detection indicators were investigated. The vibration simulation results of the gearbox obtained using MATLAB were verified with those stated in the published research articles. It was observed that as the severity of a single crack increased, the values of the time-domain statistical indicators increased, with different rates. However, the number of cracks had an adverse effect on the values of all the performance indicators, except the RMS indicator. The number and amplitude of the sidebands in the frequency spectrum were also utilized to detect the severity of the faults in each scenario. It was observed that, in the case of consecutive tooth cracks, the number of spectrum peaks and the number of cracks were well consistent in the frequency range of 4 to 5 kHz. The main finding of this study was that the peak spectral amplitude is the most sensitive indicator to the number and severity of cracks

Electrostatic Gas-Liquid Separation from High Speed Streams--Application to Advanced On-Line/On- Demand Separation Techniques

The separation of suspended droplets from gases has been one of the basic scientific and technical problems of the industrial era and this interest continues. Various industrial applications, such as refrigeration and HVAC systems, require control of fine droplets concentrations in moving gaseous mediums to maintain system functionality and efficiency. Separating of such fine droplets can be achieved using electrostatic charging as implemented in electrostatic precipitators (ESPs). They use electrostatic force to charge and collect solid particles. The objective of the present work was to study the feasibility of using wiretube electrostatic separator on the removal of fine water and oil droplets from air stream based on corona discharge ionization process. A parametric study was conducted to find key parameters affecting the separation process. This goal was approached by simulating the charging and separation phenomena numerically, and then verifying the modeling findings through experiments. The numerical methodology simulated the highly complex interaction between droplets suspended in the flow and electrical field. Two test rigs were constructed, one for air-water separation and the other for air-oil separation. A wiretube electrostatic separator was used as the test section for both test rigs. The separation performance was evaluated under different electric field and flow conditions. Finally, based on the results, a novel air-water separator prototype was designed, fabricated and tested. The numerical modeling results qualitatively showed acceptable agreement with the experimental data in terms of the trend of grade efficiency based on droplets size. Both numerical modeling results and experimental data showed that with a proper separator design, high separation efficiency is achievable for water and oil droplets. Based on the experimental data, at flow velocity of 5 m/s and applied voltage of 7.0 kV, the maximum separation efficiency for water and oil was 99.999 % and 96.267 %, respectively. The pressure drop was as low as 100 Pa and maximum power consumption was 12.0 W