Potential of heat pipe technology in nuclear seawater desalination

The official published version of this article can be found at the link below.Heat pipe technology may play a decisive role in improving the overall economics, and public perception on nuclear desalination, specifically on seawater desalination. When coupled to the Low-Temperature Multi-Effect Distillation process, heat pipes could effectively harness most of the waste heat generated in various types of nuclear power reactors. Indeed, the potential application of heat pipes could be seen as a viable option to nuclear seawater desalination where the efficiency to harness waste heat might not only be enhanced to produce larger quantities of potable water, but also to reduce the environmental impact of nuclear desalination process. Furthermore, the use of heat pipe-based heat recovery systems in desalination plant may improve the overall thermodynamics of the desalination process, as well as help to ensure that the product water is free from any contamination which occur under normal process, thus preventing operational failure occurrences as this would add an extra loop preventing direct contact between radiation and the produced water. In this paper, a new concept for nuclear desalination system based on heat pipe technology is introduced and the anticipated reduction in the tritium level resulting from the use of heat pipe systems is discussed

Ulcerative colitis associated with nephrotic syndrome after treatment with mesalazine developed into rectal carcinoma: a case study

BACKGROUND: Previous studies reported that nephrotic syndrome is associated with ulcerative colitis (UC) patients treated with mesalazine. Dysplasia associated with UC often develops into colorectal carcinoma. CASE PRESENTATION: A 17-year-old man was referred to our hospital, complaining of diarrhea and bloody stool. Total colonoscopy (TC) was performed and total-type UC was diagnosed. After treatment with mesalazine for 5 years, a low-grade dysplasia (LGD) was detected in the rectum by histological analysis of a biopsy sample. One month later, he complained of dyspnea and edema. He was diagnosed with nephrotic syndrome and administered steroid and immunosuppressant treatment: cyclosporine and mizoribine. Eight years after LGD was detected, he complained of abdominal distension and pain. Stenosis of the upper rectum by an advanced rectal carcinoma was detected. Abdominal computed tomography showed a rectal tumor with multiple lymph node metastases. Transverse colostomy was performed surgically, followed by two cycles of modified FOLFOX6 and panitumumab. He safely underwent a total proctocolectomy with a stapled ileal pouch anal-canal anastomosis, total mesorectal and bilateral pelvic lymph node dissection, and temporary loop ileostomy. Metastases were observed in 25 lymph nodes microscopically. The pathological stage of rectal carcinoma was pT3N2bM1a. After one cycle of modified FOLFOX6 postoperatively, he was discharged from the hospital. CONCLUSIONS: A patient with UC associated with nephrotic syndrome was treated with mesalazine. LGD developed into an advanced rectal carcinoma after an 8-year interval. The use of immunosuppressants for the treatment of nephrotic syndrome might affect the development of rectal carcinoma. TRIAL REGISTRATION: Trial registration: Case report registration #162

The development of a sub-atmospheric two-phase thermosyphon natural gas preheater using a lumped capacitance model and comparison with experimental results

The pre-heating of natural gas supplied to both domestic and industrial use is required to counteract the Joule–Thomson effect due to pressure reduction. Most existing pre-heaters are in the form of water bath heaters, where both the burner and exchanger are immersed in a closed water tank. These systems usually have a low efficiency, and as a result of thermal inertia have a long time lag to accommodate changes in Natural Gas (NG) mass flow rates. In this paper, the two-phase thermosyphon theory is implemented in a sub-atmospheric context to design and study a new preheating system in a transient fashion. This system is partially vacuumed (absolute pressure of 2 kPa) to lower the temperature operation range to reduce the required working fluid volume, hence reduce the required energy and improve the response time. The transient numerical model is based on a lumped capacitance method, and the full system is solved by using a fourth order Runge–Kutta method. The numerical model is validated through comparison with experimental results. Minimum efficiency of 68% has been achieved in some tests, whilst maximum efficiency of 80% in other tests. Simulations of the thermosyphon preheater system have been performed to analyse the effect of changing the working fluid volume and composition

Visualization study on the instabilities of phase-change heat transfer in a flat two-phase closed thermosyphon

This paper presents systematic experiments and visualization on the instabilities of phase-change heat transfer for water, ethanol and acetone in a flat evaporator of a two phase closed system, respectively. The effects of the heat flux, filling ratio, coolant temperature and working fluid type on the instabilities and their mechanisms have been systematically investigated. The experimental results show that the instabilities of phase-change heat transfer are strongly related to the corresponding heat transfer modes. The instabilities of temperature and heat transfer coefficient (HTC) of the evaporator are mainly caused by the bubble behaviours, the physical properties and the operation pressures. Natural convection, intermittent boiling and fully developed nucleate boiling are the main heat transfer modes in the present study. The condensate droplets may affect the instabilities due to inducing periodic boiling at lower heat fluxes. The maximum standard deviations of the evaporator temperature and vapor pressure fluctuations can reach 3.1 °C and 0.8 kPa respectively during the intermittent boiling. There is no intermittent boiling regime for ethanol and acetone in the present study. Therefore, no instability phenomena of nucleate boiling with ethanol and acetone are observed in the present study

Numerical investigation of Al2O3/water nanofluid laminar convective heat transfer through triangular ducts

In this article, laminar flow-forced convective heat transfer of Al2O3/water nanofluid in a triangular duct under constant wall temperature condition is investigated numerically. In this investigation, the effects of parameters, such as nanoparticles diameter, concentration, and Reynolds number on the enhancement of nanofluids heat transfer is studied. Besides, the comparison between nanofluid and pure fluid heat transfer is achieved in this article. Sometimes, because of pressure drop limitations, the need for non-circular ducts arises in many heat transfer applications. The low heat transfer rate of non-circular ducts is one the limitations of these systems, and utilization of nanofluid instead of pure fluid because of its potential to increase heat transfer of system can compensate this problem. In this article, for considering the presence of nanoparticl: es, the dispersion model is used. Numerical results represent an enhancement of heat transfer of fluid associated with changing to the suspension of nanometer-sized particles in the triangular duct. The results of the present model indicate that the nanofluid Nusselt number increases with increasing concentration of nanoparticles and decreasing diameter. Also, the enhancement of the fluid heat transfer becomes better at high Re in laminar flow with the addition of nanoparticles

A Novel Dual-Membranes WGS Reactor with Palladium Alloy and Polyvinyl Alcohol Membranes for Enhanced Hydrogen Recovery

A novel membrane reactor concept including palladium alloy membrane (selective to H2) and polyvinyl alcohol membrane (selective to CO2) is proposed for water gas shift reaction. The mathematical model of the reactor is developed for two reactor schemes, namely plug dual-membrane reactor (PDMR) and CSTR dual-membrane reactor (CDMR) with uni-dimensional and non-isothermal conditions. A comparison between PDMR and palladium alloy membrane reactor (PAMR) showed that PDMR volume becomes 30 % less than PAMR with 20 bar increase in feed pressure. Then the effect of Damkholer number, feed composition, and feed pressure on hydrogen recovery and CO conversion for PDMR and CDMR has been studied. Under the same operating conditions, CO conversion in PDMR is 10 % more than CDMR while its temperature decreases. The new proposed reactor configuration could pave the way for simultaneous production of hydrogen, increased CO conversion, and CO2 separation on an industrial scale

Targeting Cancer Stem Cells: A Solution to Cancer Therapy

Over the past several decades, accelerating scientific and technological advances have enabled researchers to make a great quantity of knowledge in the field of cancer biology. Numerous genes, mutant alleles, proteins, and signalling networks involved in the initiation and progression of cancer have been identified and some of the mechanisms deliberating resistance to therapy. Because of the limited efficacy of presently available treatment modalities, the cancer results to death and distress. One of the most important and complicated topics about the cancer is cancer stem cells (CSCs). The CSCs are immortal tumor-initiating cells that share some characteristics with normal stem/progenitor cells. Some of their important characteristics are self-renewal and multilineage differentiation. Since CSCs have potential resistance to chemotherapeutic agents as well as radiation therapy, it makes a serious challenge for current cancer treatments. There are various strategies for eradicating CSCs. Targeting of CSCs usually occurs by pharmacological targeting, immunotherapy and genetic targeting (miRNA,oncolytic virus). More recently, nanomedicine considerably extends the anticancer drugs, treatment strategies, and targeting CSCs. In this field, all currently available strategies could be divided into three major sections: Drug delivery targeting CSCs (nanocarriers such as nanoparticles (NPs), liposomes, micelles, nanotubes and nanogels), targeting genes of drug resistance and destruction the CSCs niches. In this review, we discussed some characteristics of CSCs and their therapeutic strategies

Role of PI3K/AKT pathway in squamous cell carcinoma with an especial focus on head and neck cancers

Abstract PI3K/AKT pathway is an important pathway in the carcinogenesis since it has central impacts in the regulation of metabolic pathways, cell proliferation and survival, gene expression and protein synthesis. This pathway has been reported to be dysregulated in several types of cancers. In the current review, we summarize the role of this signaling pathway in squamous cell carcinomas (SCCs) originated from different parts of body cervix, oral cavity, head and neck and skin. The data presented in the current review shows the impact of dysregulation of PI3K/AKT pathway in survival of patients with SCC. Moreover, targeted therapies against this pathway have been found to be effective in reduction of tumor burden both in animal models and clinical settings. Finally, a number of molecules that regulate PI3K/AKT pathway can be used as diagnostic markers for different types of SCCs

Experimental Investigation of nanofluid heat transfer in a square cross-sectional duct

English version Forced convective heat transfer of two different nanofluids including AL$_2$O$_3$-water and CuO-water in laminar flow through square cross section duct under constant heat flux has been investigated. The Nusselt number and average convective heat transfer coefficient for different nanoparticles concentrations as a function of Peclet number have been analyzed. AL$_2$O$_3$-water nanofluid with 0.2, 0.5, 1.0, 1.5, 2.0 and 2.5 percent volume fractions has been tested. The maximum enhancement of convective heat transfer coefficient for each of the above mentioned concentrations was 7, 10, 13, 18, 22, 27 percent, respectively. Also, CuO-water nanofluid was tested at 0.1, 0.2, 0.5, 0.8, 1.0 and 1.5 percent volume fractions and the results show that the maximum enhancement of convective heat transfer coefficient for each concentration was 8, 10, 14, 16, 19, 21 percent, respectively.Comment: 6 pages, in Persia

Investigating the Effect of Internal and External Religiosity on the Political Dimension of National Solidarity (Case Study: Citizens of Mashhad City)

The issue solidarity and integration among different parts and creating adaptive totalities have always been the issue of intellectuals’ thinking and action. In this arena, creating national solidarity as one of the main dimensions of social integration is among serious concerns of independent countries and among its most important benefits one can refer to establishing national security which has a deep relationship with the quiddity of people’s links to each other and people’s links to their governments in the form of integrating within countries. The waves of internal and external upheavals has become so transforming that the access to integrating components and elements in social relations seems an undeniable necessity and vitality. Therefore, re-identifying and reconstructing dynamic and sustainable canonical factors of “national cohesion” is a scientific necessity and a research requirement. Accordingly, one of the factors affecting the national solidarity in Iran is citizens’ religious attitudes in the society. The present study is meant to investigate the theoretical relationship between the two concepts of political dimension and religiosity among citizens of Mashhad City. The present study, by dividing religiosity to two internal and external types, and using the survey research, indicates that the increase in internal and external religiosity causes the increase in the political dimension of citizens’ national solidarity. DOI: 10.5901/mjss.2015.v6n5s1p41