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Enhancing the Amount of Cold Produced and Saving of the Required Input Heat using Two Different Adsorbents together in the Adsorption Ice Production AIP System
No full text A theoretical investigation of the thermal performance (coefficient of performance COP and specific cooling power SCP) of a two bed Adsorption Ice Production AIP system based on the Silica gel-methanol as adsorbent-refrigerant in the first bed and activated carbon-methanol in the second bed is presented in this paper. Two fined-tube heat exchangers were designed (named SG-bed and AC-bed) in order to generate the same desorbed refrigerant amount of 1 kgmeth and to contain two different adsorbents. The mass transfer limitations from both the two beds and the heat transfer ability between the particles of adsorbents and heat exchanger fins are taken into account in the simulated model based on the linear driving force LDF model. To desorb 1 kgmeth from the SG-bed and AC-bed a cycle simulation computer program of the AIP system was developed to investigate the effect of desorption temperature Tdes, adsorption temperature Tads and the effect of difference of the required desorption/adsorption time on the system performance and on the amount of the ice produced per cycle mice. In the present simulations, the variation of the heat source temperature from 65 to 100 oC and chilled water temperature from 15 oC to 25 oC are taken. The results showed, that the AIP system attains a coefficient of performance COP of 66 % when the AC-bed is working and attains of 44 % when the SG-bed is working. The amount of the ice produced from the system estimated to 6kg per cycle (3 kg is produced from each of bed), but the Qin input energy required to activate the AC-bed has been saved by 46 % compared with that required to activate the SG-bed. Although each of the adsorbent beds was filled with different amount of the sorption material, it is found that the mass of the sorption materials inside the both beds has no effect on the cycle time but has important effect on the specific cooling power SCP. The cycle time is strongly dependent on driven temperature of heat exchange fluid, the design of the heat exchanger and the mass transfer coefficient of sorption material Dso. An experimental set up is planned to be built to make validation of the simulation results
Failure of a Rock Slope Ten Years after Excavation
Get PDF In the present study, a rock cut slope in Chongqing of China, which failed suddenly about ten years after excavation, was reported. The survey results after failure indicated that the rock masses of the rock slope were highly fractured and heavily weathered, the critical slip surface was composed of three connected discontinuities from the toe to top of slope. The factors resulting in the failure of rock slope were mainly initial excavation and weathering process. The initial excavation removed original supporting role of the excavated rock masses at the toe of the slope to the upper unexcavated rock masses, and broken the original ground stress balance. The physical and chemical weathering after the initial excavation cracked progressively the rock masses, deteriorated the mechanic properties of the rock masses, and changed the stresses and strains in the rock slope. The stability of high artificial rock slope during operation should be paid attention to. The characteristics of geological structure, unloading induced by excavation, and weathering have important effects on the evolution for deformation of artificial rock high slope
Formulating and Performance of Quick Drying Fog Seal Material
Get PDF A new fog seal material was formulated with asphalt rejuvenator, alcohol and co-solvent. The new material provides a quick drying performance and could be used for airport runways and elevated highways. Properties of the rejuvenator used in the fog seal materials were analyzed firstly by several instruments, and its functional groups were calculated. Then, the functional groups were used in the group-contribution method and Hansen solubility parameters theory to screen out a suitable co-solvent, which should have a better solubility in alcohol. Experimental results showed that the co-solvent N-Methyl-2-Pyrrolidone could greatly improve the solubility of the rejuvenator in alcohol. Ternary phase diagram was used to optimize the formula of the fog seal material. At last, the prepared material was evaluated and showed good performances of fast drying, stability and regeneration of aged asphalt
Application of Downhole Micro-seismic Technique in Shale Gas Fracturing Optimization of Fuling, China
Get PDFThe downhole micro-seismic method has successfully applied to well fractory fracturing development in Jiaoshiba block, Fuling shale gas reservoir in September 2015. The new concept and understanding have accumulated. Combing the actual construction condition of micro-seismic monitoring in JY AA-BB well groups, we reviewed briefly the downhole micro-seismic monitoring technology and then summarized multi-disciplinary experience and understanding. The staged fracturing process level improved and productivity increased with the further development of shale gas field. Results show that the understanding of micro-seismic method has played a guiding role in the optimization of fracturing process and site construction adjustment of other wells in the same area, which increased the productivity and created a huge economic benefits with a broad market prospects
A Review on Algal Biopolymers
Get PDFPolymers are the most important materials we use in many areas of daily life. Without them humanity could not shape today’s world. However, major source of polymeric material is fossil fuels which decrease constantly. Therefore, alternative resources are needed to be discovered especially from biological source for sustainable polymer production. Biopolymers are polymers developed from renewable resources such as plant, animal, bacteria, fungi and algae. They can also be useful in material and many other applications. Algae are one of the most promising organisms in many aspects. Since they grow fast, contain variety of unique value added material and do not compete with food resources, and also they have high bioenergy feedstock potential. In this study, algae are considered as feedstock for biopolymer production and biopolymers derived from algae are investigated. Throughout this study algae derived biopolymers were classified as three types. First type of polymer obtained from algae are natural polymers (polysaccharides, lipids, extracellular polymeric substance). Especially polysaccharides from algae such as alginate and agar are well known for their biotechnological applications. Second type is polyhydroxyalkanoates (PHA) which accumulate in only cyanobacteria. And third type is bio-based polymers polymerized from algae derived monomer, they can have same characteristics with conventional synthetic polymer. This review study will give an idea especially about the algal biopolymers, their resources, properties, structures, application areas, production methods and their future potentials
A Simplified Strengthening Methodology for Minaret Structures in Turkey: Hagia Sophia Case
Get PDF Considering various types of historical buildings in Turkey, mosqs are the most common ones. Mosqs have minaret structures standing along next to the main body with dome. The minaret buildings with their own architectural and structural characteristics, are representing the cultural and historical change in different periods over the centruies. Minarets from Ottomon period are the most widespread ones in Turkey. With its cultural synthesis through out the history, minarets from Ottomon period differ from the others with structural capability. Since Turkey is a earthquke prone country, it is very important to make existing historical structures stronger against to the seismic loads. Recently, historical structures have been strengthened with fiber reinforced polymer (FRP) composites. There are numerous of research studies are available related with strengthening using FRP composites. From this standing point, in this research, a simplified and practicale strengthening methodlogy is proposed. For the investigation Hagia Sophia Minaret structures has been used as a case study. In the analysis part, Hagia Sophia Minaret structures have been investigated through time history analyses before and after FRP composite strengthening. As a result of the present research work, displacements and stress values are determined for comparison of the structural behavior of minaret structures
Vitality of The Cities
Get PDF The physical formation of city, where all members of society live, is created by non-living and tangible elements such as buildings, roads, public squares, and vegetation. On the other hand, city acquires meaning by the existence of citizens, who reinvigorate it, their behaviours within the city and the interactions between them as well as with the city. The more the citizens are actively present in the streets, the more the city is a vivid and living place. There are many studies on vitality and liveability in urban spaces. In this study, urban vitality is defined according to the information gathered from previous researches. By scrutinizing the definitions of vitality made by Lynch and Jacobs, who are leading figures in the subject of research, social interaction, sense of belongingness, and security, inclusion of different functions, transformability, aesthetics and accessibility were identified as criteria determining the urban vitality. As a result of the study, it is asserted that the cities which bear these qualifications are liveable and vivid places which can maintain their existence
Anti-Pathogenic Activity of Herbs Used in Argentinean Traditional Infusion
Get PDF The anti-pathogenic activity of Acantholippia deserticola, Haplopappus baylahuen, Lippia integrifolia and Satureja parvifolia herbs used as traditional infusion was investigated. The extracts obtained were compared with respect to chromatographic profiles and antimicrobial activities. The dichloromethane and methanol extracts of the four herbs showed significant inhibition of Staphylococcus aureus and Pseudomonas aeruginosa growth and biofilm formation. The dichloromethane extract of Lippia integrifolia that showed the highest inhibitory effect on P. aeruginosa biofilm formation, was fractionated by column chromatography using a gradient of polarity, and the activities of the fractions were evaluated. In general, the lower polar fractions inhibited biofilm in correlation with bacterial growth. However, in more polar fractions the biofilm diminution is well correlated with the inhibition of autoinducers production more than the bacterial development. The results provide scientific support for the usage of these herbs to the protection against foodborne diseases. This effect is noteworthy in L. integrifolia because the fractions showed higher growth, biofilm, and autoinducer inhibitory activity than the crude extract
The Fourier Transform of the Non-Trivial Zeros of the Zeta Function
Get PDF The non-trivial zeros of the Riemann zeta function and the prime numbers can be plotted by a modified von Mangoldt function. The series of non-trivial zeta zeros and prime numbers can be given explicitly by superposition of harmonic waves. The Fourier transform of the modified von Mangoldt functions shows interesting connections between the series. The Hilbert-Pólya conjecture predicts that the Riemann hypothesis is true, because the zeros of the zeta function correspond to eigen values of a positive operator and this idea encouraged to investigate the eigenvalues itself in a series. The Fourier transform computations is verifying the Riemann hypothesis and give evidence for additional conjecture that those zeros and prime numbers arranged in series that lie in the critical, 1/2. positive upper half plane and over the positive integers, respectively
Experimental Study on Desorption Hysteresis Characteristic for Shale Gas
Get PDF Compared with the adsorption isotherms, desorption isotherms could evaluate accurately shale absorbed gas reserves in different pressure stage, the desorption hysteresis characteristics exists in shale gas formation. In order to discover the adsorption hysteresis phenomenon and the influence factor of adsorption hysteresis in high pressure range, The physical properties test and adsorption/ desorption test of shale gas were Carried out by shale outcrop samples from horse Creek group in Eastern Sichuan. The results show that the shale gas adsorption isotherm curve and desorption isotherm curve are not coincided. It has obvious adsorption hysteresis loop, which hysteresis degree relate to shale physical parameter. It shows that the worse shale gas physical property is, the more complicated pore structure is, the more hysteresis degree appears. Meanwhile, three theoretical models were used to fit the measured isotherm adsorption and desorption curves. The results show that comparing to the Langmuir-Freudlich equation and Freundlich equation, Langmuir equation fits the adsorption and desorption characteristic of shale gas betterly