A novel solar-driven direct contact membrane-based water desalination system

This study proposes a novel integrated solar membrane-based desalination system. The system includes vacuum glass tubes to increase absorbed solar energy and to decrease heat loss, heat pipes to transfer the absorbed energy efficiently, and a tubular direct contact membrane distillation module to use the absorbed energy more effectively. To improve the freshwater production rate and overall efficiency of the proposed system, a cooling unit was also added to the permeate loop of the desalination unit. The performance of the system was experimentally investigated without (Case I) and with (Case II) the cooling unit in summer and without the cooling unit in winter (Case III) under climatic conditions of Perth, Western Australia. The experimental results indicated that except a few minutes in the morning, the heat pipe solar system was able to provide all the required thermal energy for the desalination system. The maximum thermal efficiency of the solar system in summer reached ~78% and its exergy efficiency fluctuated between 4 and 5% for a noticeable amount of time from 10:30 AM to 3 PM. Moreover, the maximum freshwater production rate were 2.78, 3.81, and 2.1 L/m2h in Cases I, II, and III, respectively. The overall efficiency of the system improved from 46.6% in Case I to 61.8% in Case II showing the technical effectiveness of implementing the cooling unit in the permeate flow loop of the system. In addition, the daily averaged specific energy consumption in Cases I, II, and III were 407, 377, and 450 kWh/m3, respectively

Performance analysis of a thermal-driven tubular direct contact membrane distillation system

This paper examines the performance of a thermal-driven tubular direct contact membrane distillation (DCMD) system theoretically and experimentally. A multi-step mathematical model was developed to predict the freshwater productivity of the tubular DCMD module applicable for both small and large-scale applications by considering the changes in the operational variables along the membrane’s length. The proposed model was verified by building an experimental rig which was tested under different operational conditions. The results showed that keeping the mass flow rates in the hot and cold channels either near the end or beyond the transition range of the flows results in higher water production. In addition, heating up the feed stream is more efficient for enhancing water productivity than using the same amount of energy to cool the permeate stream down. Finally, the effects of operational and physical factors on the freshwater productivity were identified and discussed

Thermal performance of an evacuated tube heat pipe solar water heating system in cold season

This study evaluates the performance of a heat pipe solar water heating system to meet a real residential hot water consumption pattern theoretically and experimentally under non-ideal climatic conditions during a cold day in Perth, Western Australia. A mathematical model was developed and used to calculate the optimum number of glass tubes of the heat pipe solar collector. Based on the obtained data, an experimental rig with 25 glass tubes was designed, built, and tested as the temperature changes after 25 tubes reached the insignificant value of 0.6%. The results showed that hot water extraction had significant impact on the thermal performance of solar water heating system by increasing the amount of the absorbed energy and overall efficiency and decreasing exergy destruction. This indicates the importance of considering hot water consumption pattern in design and analysis of these systems. Auxiliary heating element was a necessary component of the system and played an important role mainly at the beginning of the operation in early morning (operation time of 19 min) and partly during the cloudy and overcast periods (operation time of 8 min). Two empirical equations relating the thermal and exergetic efficiencies of the heat pipe solar collector to the operational and environmental parameters were proposed. Comparison of the theoretical and experimental outlet temperature of the collector showed very good agreement with the maximum absolute and standard errors being 5.6% and 1.77%, respectively

A review of latest developments, progress, and applications of heat pipe solar collectors

Among all the available solutions to the current high energy demand and consequent economic and environmental problems, solar energy, without any doubt, is one of the most promising and widespread solutions. However, conventional solar systems face some intractable challenges affecting their technical performance and economic feasibility. To overcome these challenges, increasing attention has been drawn towards the utilization of heat pipes, as an efficient heat transfer technology, in conventional solar systems. To the authors’ knowledge, despite many valuable studies on heat pipe solar collectors (mainly during the last decade), a comprehensive review which surveys and summarizes those studies and identifies the research gaps in this field has not been published to date. This review paper provides an overview of the recent studies on heat pipe solar collectors (HPSCs), their utilization in different domestic, industrial, and innovative applications, challenges, and future research potentials. The concept and principles of HPSCs are first introduced and a review of the previous studies to improve both energy efficiency and cost effectiveness of these collectors is presented. Moreover, a concise section is dedicated to mathematical modeling to demonstrate suitable methods for simulating the performance of HPSCs. Also, the latest applications of HPSCs in water heating, desalination, space heating, and electricity generation systems are reviewed, and finally, some recommendations for future research directions, regarding both development and new applications, are made

Strategies to improve the thermal performance of heat pipe solar collectors in solar systems: A review

Invention of evacuated tube heat pipe solar collectors (HPSCs) was a huge step forward towards resolving the challenges of conventional solar systems due to their unique features and advantages. This has led to their utilization in a wide range of solar applications surpassing other conventional collectors. However, relatively low thermal efficiency of heat pipe solar (HPS) systems is still the major challenge of solar industry evidenced by numerous studies conducted mainly during the last decade to improve their efficiency. To date, several review papers have been published summarizing studies relevant to utilization of HPSCs in various thermal applications. However, to the authors\u27 knowledge, a comprehensive review which surveys and provides an overview of the studies undertaken to improve the thermal performance of HPS systems (mainly during the last decade) by implementing different strategies has not been published to date. This review paper summarizes all the proposed strategies to improve the thermal efficiency of different industrial, domestic, and innovative HPS systems. First, the concept, structure, and operational principles of HPSCs are introduced concisely. Then, novel structures and designs of HPSCs aiming to increase the thermal efficiency of the collector as the most important component of the solar system is reviewed. This is followed by a comprehensive review of various methods to store solar energy more efficiently, increase solar system’s operation time, increase overall efficiency by turning the solar system into a multi-purpose system, enhance heat transmission in the solar system, and implement new solar loop and heat pipe working fluids with better heat transfer characteristics. Finally, research gaps in this field are identified and some future research trends and directions are recommended

Treatment of Kidney Stones Using Extracorporeal Shock Wave Lithotripsy (ESWL) and Double-J Stent in Infants

Background. Extracorporeal shock wave lithotripsy (ESWL) has progressively acquired popularity as being the gold standard treatment for upper urinary tract lithiasis in infants since 1980. Our aim was to evaluate the outcome of ESWL for kidney stones and the use of double-J stent in infants. Material and Methods. A prospective clinical trial study performed on 50 infants with renal calculi at pelvic admitted in the Urology ward of Shafa Hospital, Sari, Iran, between 2001 and 2010. Main outcome measure of our study was clearing stones after one or more consecutive sessions of ESWL. Results. The study included 50 patients with renal calculi at pelvic. Among them, there were 35 (70%) boys and 15 (30%) girls with the age ranging from 1 to 13 months (mean of 7 month ± 3 days). All of them were treated by standard ESWL using Simons Lithostor plus machine. The stone sizes ranged from 6 mm to 22 mm. Double-J stents were placed in 11 infants (22%) with stones larger than 13 mm. Most of the patients required only one ESWL session. Conclusion. Since there were no complications following ESWL treatment, we can conclude that, in short term, ESWL is an effective and safe treatment modality for renal lithiasis in infants. In addition, we recommend double-J stent in infants with stones larger than 13 mm

Health Poverty Trend among families with child using Health Financial Contribution and cohort approach: 1984-2012

Background and Aims: Health is an important dimension in analyzing multidimensional child poverty. High life expenditure imposed on families has lead to the household’s health poverty. Considering the importance of childhood and measuring health poverty indices to inform planners and towards distributive effects of policy strategies, as well as, family welfare, this paper tends to measure and analyse the trends of health poverty of Iranian “households with child” from 1984-2012.Materials and Methods: In this trend study, statistical data on household budgets were considered to measure health poverty in households with child (using FGt index). The results were analyzed using STATA and Excel Software.Results: The results showed that the poverty rate was the highest in terms of all age group’s health in 1999. While, the health poverty rate among families with children in the age group of 11-15-year-old showed an upward trend in recent periods (the end of the fourth development goal and beginning of fifth Program), it was associated with fluctuations in other age groups.Conclusion: Overall, health poverty rate was high in all age groups although it showed high fluctuations. The high fluctuations of the health poverty index during the development plans indicate that stable and consistent policy has not been developed to reduce households facing catastrophic health expenditure. At the end of this research, some recommendations have been offered to reduce the amount of household’s health poverty.Key words: health poverty, household financial contribution, cohort approach, chil

Effects of Zingiber officinale as Feed Additive on the Common Carp Body Composition

The present study was conducted to evaluate the use of ginger powder in diet of common carp, Cyprinus capio (27±3 gr). Different levels of the plant powder (0, 0.25.0.5, 1 and 2 gr / per 100gr food) were spread on commercial diet. The feed was offered by 8 weeks. Results showed that fish fed experimental diets had no significant difference (P>0.05) in amount of NFE, but have significant difference in protein, lipid, ash, moisture percent and kcal energy from different diet (p<0.05) while in kruskal-wallis test illustrated significant difference in amount of carbohydrate and body fiber (p<0.05). So, the best results in amount of protein, lipid, and energy shown in maximum dosage of ginger powder in carp commercial diet  and low amount of them shown in control group.  There were high amount of carbohydrate and low amount of fiber in control group. There was the lack of fiber in control group and upper level of ash in the third treatment. So, this study presents that; to be improving the body composition of common carp we use the herbal medicine like Ginger powder in their commercial diets

Open quantum system approach to the gravitational decoherence of spin-1/2 particles

This paper investigates the decoherence effect resulting from the interaction of squeezed gravitational waves with a system of massive particles in spatial superposition. We take into account two systems, one made up of spin-1/2 particles and the other of spinless particles, and use the quantum Boltzmann equation to study their decoherence. For the spin-1/2 particle system, our analysis reveals that the rate of decoherence depends on both the squeezing strength and the squeezing angle of the gravitational waves. Our results demonstrate that squeezed gravitational waves with squeezing strengths of $r_p\geq1.2$ and a squeezing angle of $\varphi_p=\pi/2$ can induce a 1 % decoherence within 1 s free falling of a cloud of spin-1/2 particles. In contrast, for the spinless particle system, the decoherence rate is weaker and depends solely on the squeezing strength of the gravitational waves and does not depend on the squeezing angle. As a consequence, in this case, the same amount of decoherence of the spin-1/2 particles can be reached when the system is two orders of magnitude more massive, the experiment ten times longer, and for squeezing strength $r_p\geq2.1$. This investigation sheds light on the relationship between squeezed gravitational waves and the coherence of spatial superposition states in systems of massive particles and their spin. The dependence of decoherence on squeezing strength and, in the case of spin-1/2 particles, on the squeezing angle paves the way for further exploration and understanding of the quantum-gravity connection. We suggest that such an experimental setup could also be employed to eventually investigate the level of squeezing effect (and hence quantum-related properties) of gravitational waves produced in the Early Universe from inflation.Comment: 40 pages, 8 figure

Probing Virtual ALPs by Precision Phase Measurements: Time-Varying Magnetic Field Background

We propose an experimental scheme for detecting the effects of off-shell axion-like particles (ALPs) through optical cavities. In this proposed experiment, linearly polarized photons are pumped into an optical cavity where an external time-dependent magnetic field is present. The magnetic field mediates an interaction between the cavity photons and ALPs giving rise to a modification in the phase of the cavity photons. The time-dependent nature of the external magnetic field prompts a novel amplification effect which significantly enhances this phase modification. A detection scheme is then proposed to identify such axion-induced phase shifts. We find that the phase modification is considerably sensitive to the photon-ALPs coupling constants $g_{a\gamma\gamma}$ for the range of ALPs mass $3.1\:\mu\textrm{eV}\leqslant m_a \leqslant 44.4\:\mu\textrm{eV}$.Comment: 26 pages, 8 figure