Energy, Exergy, and Environmental (3E) Analysis of Hydrocarbons as Low GWP Alternatives to R134a in Vapor Compression Refrigeration Configurations

The phase-down of hydrofluorocarbons and substitution with low global warming potential values are consequences of the awareness about the environmental impacts of greenhouse gases. This theoretical study evaluated the energy and exergy performances and the environmental impact of three vapor compression system configurations operating with the hydrocarbons R290, R600a, and R1270 as alternatives to R134a. The refrigeration cycle configurations investigated in this study include a single-stage cycle, a cycle equipped with an internal heat exchanger, and a two-stage cycle with vapor injection. According to the results, the alternative hydrocarbon refrigerants could provide comparable system performance to R134a. The analysis results also revealed that using an internal heat exchanger or a flash tank vapor injection could improve the system’s efficiency while decreasing the heating capacity. The most efficient configuration was the two-stage refrigeration cycle with vapor injection, as revealed by the exergy analysis. The environmental impact analysis indicated that the utilization of environmentally-friendly refrigerants and improving the refrigeration system’s efficiency could mitigate equivalent CO2 emissions significantly. The utilization of hydrocarbons reduced the carbon footprint by 50%, while a 1% to 8% reduction could be achieved using the internal heat exchanger and flash tank vapor injection

S-system theory applied to array-based GNSS ionospheric sensing

The GPS carrier-phase and code data have proven to be valuable sources of measuring the Earth’s ionospheric total electron content (TEC). With the development of new GNSSs with multi frequency data, many more ionosphere-sensing combinations of different precision can be formed as input of ionospheric modelling. We present the general way of interpreting such combinations through an application of S-system theory and address how their precision propagates into that of the unbiased TEC solution. Presenting the data relevant to TEC determination, we propose the usage of an array of GNSS antennas to improve the TEC precision and to expedite the rather long observational time-span required for high-precision TEC determination

Synthesis of a heulandite-type zeolite by hydrothermal conversion of zeolite P1

A synthetic analogue of the zeolite heulandite is synthesized by hydrothermal treatment of zeolite P1 with solutions containing CaCl_2 and NaOH

Study on effect of Rosmarinus officinalis and Zataria multiflora extracts on the stability of fatty acids in frozen silver carp minced

In this study, the effect of Rosemary and Zataria extracts on three different treatments in frozen Silver carp minced were studied in normal packaging. Therefore, a control and three treatments were defined: Treatment 1 - Control: frozen meat packaged in conventional Treatment 2: Frozen Silver carp minced + Zataria 300mg/kg in normal packaging Treatment 3: Frozen Silver carp minced + Rosemary 200mg/kg in normal packaging Treatment 4: Frozen Silver carp minced + Rosemary compound (100mg/kg) and Zataria (100mg/kg) in normal packaging After quick freezing of samples in the spiral freezer by individual quick freezing method, to maintain the cold temperature (-18)°C were transferred. For six month, Sampling and measurements to determine the fatty acid profile of the zero phase beginning in the first month and then every ten days, and 15 days in the second month of the third month after the monthly test. Identifying, defining and measuring the fatty acid profile by gas chromatography was performed. In this study, levels of both saturated and unsaturated fatty acids in three experimental and one control were identified as follows: A: SFA: (Saturated Fatty Acid): Meristic C14: 0/ Palmitic C16: 0 /Hepta decaenoic C17: 0 / Stearic C18: 0 / Arashidic C20: 0 B: (MUFA Mono Unsaturated Fatty Acid): Palmitoleic C16: 1-W7 / Oleic C18: 1-W9 /Gadoleic C20: 1 - W9 C: (PUFA Poly Unsaturated Fatty Acid): Linoleic C18: 2-W6 /α-Linolenic C18:3-W3 D: (HUFA High Unsaturated Fatty Acid): Arachidonic C20: 4 - W6 Eicosa panta enoic acid C20: 5- EPA/W3 Docosa hexa enoic acid C22: 6-DHA/W3. Results of this study was to determine keep frozen fish meat containing extracts of Zataria and Rosemary in freezing conditions, stability of different types of fatty acids, mono unsaturated fatty acids, poly unsaturated fatty acids, high unsaturated fatty acids, So that none of the fatty acids measured, were not observed increase or decrease Changes over time while maintaining the oxidation of fatty acids is minimized. The results obtained from the profile of fatty acids and their related indices and statistical tests show the treatment contains Rosemary extract show greater stability than thyme during storage (- 18)°C. According to studies, Frozen minced fish meat treated with extracts of Rosemary, was used until the end of the storage period

The LHC Logging Service : Handling terabytes of on-line data

Based on previous experience with LEP, a long-term data logging service for the LHC was developed and put in place in 2003, several years before beam operation. The scope of the logging service covers the evolution over time of data acquisitions on accelerator equipment and beam related parameters. The intention is to keep all this time-series data on-line for the lifetime of LHC, allowing easy data comparisons with previous years. The LHC hardware commissioning has used this service extensively prior to the first beams in 2008 and even more so in 2009. Current data writing rates exceed 15TB/year and continue to increase. The high data volumes and throughput rates, in writing as well as in reading, require special arrangements on data organization and data access methods

ANN Modeling to Analyze the R404A Replacement with the Low GWP Alternative R449A in an Indirect Supermarket Refrigeration System

Artificial neural networks (ANNs) have been considered for assessing the potential of low GWP refrigerants in experimental setups. In this study, the capability of using R449A as a lower GWP replacement of R404A in different temperature levels of a supermarket refrigeration system is investigated through an ANN model trained using field measurements as input. The supermarket refrigeration was composed of two indirect expansion circuits operated at low and medium temperatures and external subcooling. The results predicted that R449A provides, on average, a higher 10% and 5% COP than R404A at low and medium temperatures, respectively. Moreover, the cooling capacity was almost similar with both refrigerants in both circuits. This study also revealed that the ANN model could be employed to accurately predict the energy performance of a commercial refrigeration system and provide a reasonable judgment about the capability of the alternative refrigerant to be retrofitted in the system. This is very important, especially when the measurement data comes from field measurements, in which values are obtained under variable operating conditions. Finally, the ANN results were used to compare the carbon footprint for both refrigerants. It was confirmed that this refrigerant replacement could reduce the emissions of supermarket refrigeration systems

Morphology control in polymerized high internal phase emulsion templated via macro-RAFT agent composition: visualizing surface chemistry

A series of polymerized high internal phase emulsion (polyHIPE) materials have been prepared by using a water in oil emulsion stabilized by a macro-RAFT agent, 2-(butylthiocarbonothioylthio)-2-poly(styrene)-b-poly(acrylic acid), acting as a polymeric surfactant. The pore structures of the formed polyHIPEs were closed. By removing the RAFT-endgroup of the amphiphilic macro-RAFT agent, the obtained polyHIPEs possessed an open structure with voids. The effect of the RAFT-endgroup of the amphiphilic macro-RAFT agent on the surface chemistry of the polyHIPEs is discussed. The obtained polyHIPEs via this surfactant-assisted functionalization strategies were characterized by FTIR spectroscopy, FTIR mapping, SEM, SEM-EDX, TEM, XPS as well as synchrotron-based scanning transmission X-ray microscopy (STXM). The latter technique revealed the surface chemistry of the obtained polyHIPEs and macro-RAFT agent multicomponents with a surface spatial resolution of the order of 30–100 nm.A. Khodabandeh, R. D. Arrua, B. R. Coad, T. Rodemann, T. Ohigashi, N. Kosugi, S. C. Thickett and E. F. Hilde

Survey the effects of live rainbow trout handling on fish meat quality

This research was performed to survey the live handling condition of Rainbow trout in Tehran province and determine the effects of this method on the quality of the flesh regarding with water binding capacity, pH changes, moisture, fat and protein content in different seasons of year. Based on reviews of Questionnaires, there were 20 main live rainbow trout sale centers in Tehran. 10 numbers of these were in fruit and vegetable centers of municipality and others were out of these centers. Live fish handling to in these areas mainly was performed from fish farms located in the Haraz road (85 percent), farms of Firoozkooh road (10 percent) and others were (5 percent) from neighboring provinces. The results of this study indicated that current methods of live handling in Tehran (the transporting time 4 h and the density of fish in tank 100-150 kg /m^2) meat quality of transported trout was not affected. Water holding capacity of transported fish was less than caught fish in the fields. This amount was reached to lowest level in in summer as well as the differences between the two groups were significant (P<0.05). Also, when a meat pH level was elevated, water holding capacity was reduced. In summer, the amount of WHC in transported fish was 13.4% that was a highest value between the seasons. Appears that in the summer, high temperature and increasing kinds of stresses to fish during handling due to excessive accumulation of metabolites such as ammonia, muscle energy sources emptied because of high activity. In this condition, falling of pH during postmortem changes being moderated and lead to increase drip loss in the transported sample

On biases in precise point positioning with multi-constellation and multi-frequency GNSS data

© 2016 IOP Publishing Ltd. Various types of biases in Global Navigation Satellite System (GNSS) data preclude integer ambiguity fixing and degrade solution accuracy when not being corrected during precise point positioning (PPP). In this contribution, these biases are first reviewed, including satellite and receiver hardware biases, differential code biases, differential phase biases, initial fractional phase biases, inter-system receiver time biases, and system time scale offset. PPP models that take account of these biases are presented for two cases using ionosphere-free observations. The first case is when using primary signals that are used to generate precise orbits and clock corrections. The second case applies when using additional signals to the primary ones. In both cases, measurements from single and multiple constellations are addressed. It is suggested that the satellite-related code biases be handled as calibrated quantities that are obtained from multi-GNSS experiment products and the fractional phase cycle biases obtained from a network to allow for integer ambiguity fixing. Some receiver-related biases are removed using between-satellite single differencing, whereas other receiver biases such as inter-system biases are lumped with differential code and phase biases and need to be estimated. The testing results show that the treatment of biases significantly improves solution convergence in the float ambiguity PPP mode, and leads to ambiguity-fixed PPP within a few minutes with a small improvement in solution precision