Hydrogen storage in single wall carbon nanotubes produced on iron catalyst

Hydrogen is a promising clean energy alternative to conventional energy sources. Hence, increasing demand on hydrogen as energy carrier enhances studies in hydrogen storage. Hydrogen should be safely and efficiently stored in order to overcome existing barriers in hydrogen usage. Single wall carbon nanotube (SWCNT) is an eligible material for hydrogen storage. In this study, SWCNTs were produced by catalytic chemical vapor deposition (CCVD) of acetylene (C2H2) on MgO powder substrate impregnated with Fe. Catalysts were prepared with Fe to MgO ratio of 5:100 using iron nitrate (Fe(NO3)3•9H2O) solution as Fe source. SWCNTs were synthesized at 800°C for 60 minutes. Nitric acid (HNO3), was used for purification of synthesized SWCNT. The aim of the research was to investigate hydrogen storage capacity of as produced and purified SWCNTs synthesized on Fe-MgO catalyst. The morphology and structure of the SWCNTs were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis. Thermal gravimetric analysis (TGA), and Raman spectroscopy were used for further characterization. Hydrogen storage capacities of SWCNTs were measured by high pressure volumetric analyzer using volumetric method at the cryogenic temperature and gas pressure up to 90 bar. It was found that the hydrogen adsorption capacities of these materials were around 1.9 and 5.3 wt% for as produced and purified SWCNTs respectively. With the fact that DOE target for 2015 is 5.5 wt%, it was seen that SWCNTs produced on Fe-MgO catalyst have good potential as hydrogen storage material

Effects of Ecocnomic Crisis on Marital Fertility in Turkey

The relations between demographic indicators and economic business cycles have been proven many times for historical and modern populations. The results from these studies indicated clear connections for demography and economy. Absence of this study for Turkey motivated me to investigate this phenomenon from marital fertility aspect. The aim of the study is to analyze the clear marital fertility responses to economic crisis for different characteristics of individuals in different parts of Turkey. To apply this, micro demographic data is combined with macro economic data for event history analysis purpose. The results indicated that the relation between marital fertility and economic fluctuations occurs as expected for Turkey. Also, the results provided important knowledge about the marital fertility responses of specific characteristics individuals to economic fluctuations and social differences between regions of Turkey

The effect on anxiety level of coronary angiographic result and the perception of pain

Background: The problems and complications experienced by the patients who underwent a CAG due to their pain and anxiety can be minimized through a care plan prepared to meet their needs and a coordinated teamwork. In this prospective and descriptive study we aimed at determining the effect of coronary angiography results and perceived pain on anxiety level in patients who undergoing coronary angiography.Methods: The study was carried out with patients who were implemented coronary angiography for the first time at the cardiology clinic of Osmaniye private new life hospital between May 2014 and August 2014. The study data were collected using the State-Trait Anxiety Inventory (STAI), a verbal pain rating scale and a questionnaire that was prepared by the investigators. The descriptive data are given in the form of arithmetic mean Standard Deviation (SD), numbers and percentage distribution. The correlations between the variables were assessed using crosstabs, one-way ANOVA and the Pearson's correlation analysis. The data were evaluated in 95% confidence interval and at a significance level of P <0.05.  Results: 35.9% of the patients stated that they felt severe pain. The mean anxiety score was 36.746.81 and those who felt very severe and unbearable pain had higher mean anxiety scores (P <0.01). Those who had three coronary diseases had higher anxiety levels (41.149.30) than those who had an atherosclerotic stenosis and #8805;50% (normal) (35.945.49) (P <0.01). Gender had an influence on pain levels (P <0.01).  Conclusion: Coronary angiography results and pain perception were determined to be statistically significant effects on anxiety level. A statistically significant correlation was found between pain and anxiety. In general, pain and anxiety affect each other positively; an increase in one results in an increase in the other.

The effects of family support and work engagement on organizationally valued job outcomes

There are calls for more empirical research about the antecedents and outcomes of work engagement in frontline service jobs in the hospitality management literature. With this realization, using the precepts of the motivational process of the Job Demands-Resources model, the present study aims to develop and test a conceptual model that examines work engagement as a mediator of the effect of family support on organizationally relevant and valued job outcomes. Turnover intentions, job performance, and extra-role customer service are the outcomes investigated in this study. Data collected from frontline employees with a time lag of two weeks in the international five-star chain hotels in Turkey were used to gauge these relationships. The results from structural equation modeling provide empirical support for all hypothesized relationships. Specifically, frontline employees who receive sufficient support in the family domain are highly engaged in their work. These employees in turn are less inclined to leave the current organization. They also display in-role and extra-role performances at elevated levels in the workplace. In short, work engagement functions as a full mediator of the impact of family support on turnover intentions, job performance, and extra-role customer service. Implications of the results and future research directions are discussed in the article

Analysis of spatial fixed PV arrays configurations to maximize energy harvesting in BIPV applications

This paper presents a new approach for efficient utilization of building integrated photovoltaic (BIPV) systems under partial shading conditions in urban areas. The aim of this study is to find out the best electrical configuration by analyzing annual energy generation of the same BIPV system, in terms of nominal power, without changing physical locations of the PV modules in the PV arrays. For this purpose, the spatial structure of the PV system including the PV modules and the surrounding obstacles is taken into account on the basis of virtual reality environment. In this study, chimneys which are located on the residential roof-top area are considered to create the effect of shading over the PV array. The locations of PV modules are kept stationary, which is the main point of this paper, while comparing the performances of the configurations with the same surrounding obstacles that causes partial shading conditions. The same spatial structure with twelve distinct PV array configurations is considered. The same settling conditions on the roof-top area allow fair comparisons between PV array configurations. The payback time analysis is also performed with considering local and global maximum power points (MPPs) of PV arrays by comparing the annual energy yield of the different configurationsPeer ReviewedPostprint (author’s final draft

The effect of gender on the complications, pain intensity and pain management in hemodialysis patients

Background: Chronic renal failure (CRF) is a disease which threatens life, leads to significant loss of manpower and various complications, affecting almost every age group, mostly young adults. In the present study aim was to determine the effects to the complications, pain severity and pain management of gender differences in patients having HD treatment.Method: This study was a descriptive study. Data in research; patient information form, form questioning the way of pain management types, visual analog scale (VAS) were used.Results: Muscle cramps and nausea that show statistically significant differences between men and women, were more commonly seen in women (p≤0.05). HD applied CRF patients, they experienced musculoskeletal pain associated with most (36.9%) were determined to experience the more women than men (p<0.05). Perceived pain intensity was significantly higher in women (p<0.05).Conclusion: It was determined that patients had complications mostly muscle cramps, so their pain reasons are mostly related to musculoskeletal system and they had moderate pain, women had much more complications and pains related to musculoskeletal system

Measurements of noise at crossroads and on transportations, its effects and possible measures to take

Noise has some effects which can be explained under the titles as ‘psychological’, ‘physical’, ‘physiological’, and ‘related to performance’. The psychological effects are general feeling of annoyance, boredom, bad-temper, and behavioural disorders; the physiological effects are the increase in blood pressure, faster breathing and pulsation, changes in body activities, disorders in blood circulation and sudden reflexes. The physical effects are temporary or permanent hearing damage. The effects on performance are associated with difficulty in concentration, lack of movement, and decrease in efficiency at work. It may not be possible to keep noise at normal levels in every condition but it may be possible to keep its effects under control by various arrangements and preventions. The measurement and definition of the noise, desired to be kept under control, by accurate methods and systems is a determinative factor in prevention of noise. For this aim the noise measurements were applied in Kadikoy, on the Anatolian Side of the city of Istanbul. In the research the measurements were made on five major crossroads and on mass transportations and the results were analyzed. The time of the measurements was randomly selected within working hours on weekdays. The data were obtained at certain periods of time from different spots and the results were presented

Big Data Meets Telcos: A Proactive Caching Perspective

Mobile cellular networks are becoming increasingly complex to manage while classical deployment/optimization techniques and current solutions (i.e., cell densification, acquiring more spectrum, etc.) are cost-ineffective and thus seen as stopgaps. This calls for development of novel approaches that leverage recent advances in storage/memory, context-awareness, edge/cloud computing, and falls into framework of big data. However, the big data by itself is yet another complex phenomena to handle and comes with its notorious 4V: velocity, voracity, volume and variety. In this work, we address these issues in optimization of 5G wireless networks via the notion of proactive caching at the base stations. In particular, we investigate the gains of proactive caching in terms of backhaul offloadings and request satisfactions, while tackling the large-amount of available data for content popularity estimation. In order to estimate the content popularity, we first collect users' mobile traffic data from a Turkish telecom operator from several base stations in hours of time interval. Then, an analysis is carried out locally on a big data platform and the gains of proactive caching at the base stations are investigated via numerical simulations. It turns out that several gains are possible depending on the level of available information and storage size. For instance, with 10% of content ratings and 15.4 Gbyte of storage size (87% of total catalog size), proactive caching achieves 100% of request satisfaction and offloads 98% of the backhaul when considering 16 base stations.Comment: 8 pages, 5 figure

Big Data Caching for Networking: Moving from Cloud to Edge

In order to cope with the relentless data tsunami in $5G$ wireless networks, current approaches such as acquiring new spectrum, deploying more base stations (BSs) and increasing nodes in mobile packet core networks are becoming ineffective in terms of scalability, cost and flexibility. In this regard, context-aware $5$G networks with edge/cloud computing and exploitation of \emph{big data} analytics can yield significant gains to mobile operators. In this article, proactive content caching in $5$G wireless networks is investigated in which a big data-enabled architecture is proposed. In this practical architecture, vast amount of data is harnessed for content popularity estimation and strategic contents are cached at the BSs to achieve higher users' satisfaction and backhaul offloading. To validate the proposed solution, we consider a real-world case study where several hours of mobile data traffic is collected from a major telecom operator in Turkey and a big data-enabled analysis is carried out leveraging tools from machine learning. Based on the available information and storage capacity, numerical studies show that several gains are achieved both in terms of users' satisfaction and backhaul offloading. For example, in the case of $16$ BSs with $30\%$ of content ratings and $13$ Gbyte of storage size ($78\%$ of total library size), proactive caching yields $100\%$ of users' satisfaction and offloads $98\%$ of the backhaul.Comment: accepted for publication in IEEE Communications Magazine, Special Issue on Communications, Caching, and Computing for Content-Centric Mobile Network