104 research outputs found
"Asset Poverty in The United States: Its Persistence in an Expansionary Economy"
No full textFrom this paper's Preface, by Dr. Dimitri B. Papadimitriou, President: Economic growth and a rising stock market in the 1990s gave the impression that everyone was accumulating wealth and asset poverty rates were declining. The impression was supported by the official, income-based poverty measure, which exhibited a sharp decline. According to Senior Scholar Edward N. Wolff and Research Scholar Asena Caner, poverty measures should include wealth as well as income. Their study of asset poverty in the United States between 1984 and 1999 focuses on the lower end of the wealth distribution and shows that asset poverty rates did not decline during the period studied, and that the severity of poverty increased. It also shows that asset poverty is much more persistent than income poverty.
Process length variation in cysts of a dinoflagellate, Lingulodinium machaerophorum, in surface sediments: Investigating its potential as salinity proxy
No full text“Many authors have contributed to writing this paper. Those listed in the metadata are: the main/contact author, the first listed author and Brunel University author(s). For a full list of the authors, please see the PDF version.”A biometrical analysis of the dinoflagellate cyst Lingulodinium machaerophorum (Deflandre and Cookson 1955) Wall, 1967 in 144 globally distributed surface sediment samples revealed that the average process length is related to summer salinity and temperature at a water depth of 30 m by the equation (salinity/temperature) = (0.078*average process length + 0.534) with R² = 0.69. This relationship can be used to reconstruct palaeosalinities, albeit with caution. The particular ecological window can be associated with known distributions of the corresponding motile stage Lingulodinium polyedrum (Stein) Dodge, 1989. Confocal laser microscopy showed that the average process length is positively related to the average distance between process bases (R²=0.78), and negatively related to the number of processes (R²=0.65). These results document the existence of two end members in cyst formation: one with many short, densely distributed processes and one with a few, long, widely spaced processes, which can be respectively related to low and high salinity/temperature ratios. Obstruction during formation of the cysts causes anomalous distributions of the processes. From a biological perspective, processes function to facilitate sinking of the cysts through clustering
Maximum extension and regression rate of cutaneous sensory block obtained with the external oblique intercostal block or the modified thoracoabdominal nerves block through perichondrial approach in patients undergoing laparoscopic cholecystectomy
No full textBACKGROUND: Several studies demonstrate that both external oblique intercostal block (EOIB) and modified thoracoabdominal nerves block through perichondrial approach (M-TAPA) contribute to analgesia in the anterior abdomen by targeting the thoracoabdominal nerves through distinct pathways. However, the sensory assessment and dermatomal analysis remain poorly understood. METHODS: This prospective observational study aimed to determine the sensory assessment and dermatomal regression rate of EOIB and M-TAPAin patients undergoing laparoscopic cholecystectomy. The study included a total of 24 patients, with 12 patients in each group. Blocks were performed bilaterally, administering 25 mLof bupivacaine 0.25% for each side, resulting in a total volume of 50 mL. The anterior abdominal wall was vertically partitioned into the midabdomen, left-lateral abdomen, and right-lateral abdomen, and horizontally divided into the epigastric, umbilical, and hypogastric regions. Sensory block was assessed at the 45th minute with cold stimulus and pinprick. Subsequent evaluations were at intervals of 6, 10, 14, 18, 22, and 24 hours. RESULTS: The blocked area percentile with cold sensation in the anterior abdomen was 43.07% (36.67-55.74) with EOIB, 40.49% (34.05-43.67) with M-TAPA(P=0.3219). When the region above the intertubercular plane was examined with cold sensation, EOIB covered 55.92% (46.75-62.07), and M-TAPAcovered 49.60% (40.39-54.03) of the epigastric and umbilical areas. Assessment of the midabdominal portion of the anterior abdomen revealed that the blocked area percentile was statistically significantly higher in the M-TAPA group with both cold sensation and pinprick. At 45 minutes, the percentage of blocked dermatomes was 100% between T7-T8 in the EOIB group and between T7-T10 in the M-TAPAgroup. Both groups exhibited lower success rates in dermatomes T5 and T12, with no sensory block within the L1 dermatome, and cutaneous dermatomal block status either absent or negligible after 24 hours. All trocar entries were located within the cutaneous sensory block for both blocks, except for trocar C, which was located most laterally. CONCLUSIONS: Bilateral EOIB and M-TAPAproduce a comparable sensory cutaneous block in the anterior abdomen, particularly in the umbilical and epigastric regions. Additionally, the midabdominal cutaneous blocked area was greater in patients undergoing M-TAPA, suggesting a more consistent distribution along the anterior cutaneous branches of the thoracoabdominal nerves
Low volume store planning for workload balancing and truckload
No full textOkutkan, Caner (Dogus Author) -- Çelepçıkay, Ömer (Dogus Author) -- Çimen, Egemen Berki (Dogus Author)In this study, it is aimed to decrease the number of days planned to be shipped in stores with low sales volume, to create a balanced work load and to increase vehicle occupancy capacity . Particularly, Less than Truckload problem is analyzed and model in this study. The techniques used in this study showed that adaptability can be achieved with shipment and store planning as well as green supply chain environment to minimize Less than Truckload (LTL) as well as gas consumption. A mathematical model was created in the direction of multi objective problem and solved in the GAMS environment. Moreover, scenario analyzes were made and the study was tested on five specially identified regions on Turkey
ORTA GELİR TUZAĞINDAN ÇIKMA YOLUNDA YETİŞKİN BECERİLERİ: PIAAC 2012-2015 VERİLERİ
No full textOrta gelir tuzagindaki ulkeler arasinda gosterilen Turkiye’nin ust gelir grubuna cikabilmek icin yenilikci bir ekonomi yaratmasinin gerekliligi ve bu nedenle nitelikli bir beseri sermayeye ihtiyac duydugu literaturde vurgulanmaktadir. Gerek dusuk bagimli nufus orani sayesinde acik olan demografik firsat penceresi gerekse hizla artan okullasma oranlari Turkiye icin onemli avantajlar yaratmaktadir. Bu calismanin amaci OECD tarafindan yurutulen PIAAC arastirmasi verileri araciligiyla Turkiye’nin beseri sermaye duzeyini ve farkli sosyo-ekonomik degiskenlerin beseri sermaye uzerindeki etkisini tespit etmektir. PIAAC verilerine gore sozel, sayisal ve teknoloji zengin ortamlarda problem cozme becerileri konusunda Turkiye OECD ulkelerinin cok gerisinde yer almaktadir. Bu beceri alanlarinda genc yas gruplarina dogru bir artis olsa da Turkiye’nin ust gelir grubuna cikmasini saglayacak beseri sermayeyi olusturmaktan cok uzak oldugu gorulmektedir. Ayrica, yetiskin becerileri konusunda cesitli sosyo-ekonomik degiskenlere gore ciddi esitsizlikler oldugu da ortaya cikmaktadir. http://dx.doi.org/10.17130/ijmeb.2019CEEIK20185410
Noot bij: HvJ EU 12 april 2016, JV, 2016, 133 (Caner Genc)
No full textContains fulltext :
166413.pdf (Publisher’s version ) (Open Access)12 april 201
Comparative gasketed plate heat exchanger performance prediction with computations, experiments, correlations and artificial neural network estimations
No full textGasketed plate heat exchangers (GPHEX) are popular due to their small volume, ease of cleaning and high thermal performance. Hydraulic and thermal performance of GPHEX are not as easily determined since they solely depend on the corrugation pattern of the heat exchanger (HEX) plates. Every plate needs its own correlation for Nusselt number and friction factor. Correlation development based on plate-specific experiments is one method of performance prediction. Computational fluid dynamics (CFD) is also applicable to understand the Nusselt number and friction characteristics. However, since it is difficult to observe the effects of the corrugation pattern computationally, the pattern of the plates is usually ignored and CFD is performed on flat, nonpatterned plates. In addition, correlations developed using experimental data can not exactly predict the performance. In this article, GPHEX computations are performed with corrugated plates and the results are validated via comparison with experiments performed for the same HEX plates. The use of corrugation patterns in computations is justified with the help of experimental results, and corrugated and flat-plate HEX computations. Artificial neural networks (ANNs) based on experimental findings are used as an alternative to correlations to examine the performance. The results show that ANNs can depict the experimental trends better than the correlations. The ANN results, which are composed of 12 inputs, and two hidden layers consisting of 10 and six neurons, respectively, are within 16% of the experimental results, as opposed to the correlations, which are within 40%
Experimental determination of NiFe2O4-water nanofluid thermophysical properties and evaluation of its potential as a coolant in polymer electrolyte membrane fuel cells
No full textHeat is generated as a byproduct of the electrochemical reactions of a polymer electrolyte membrane fuel cell. This heat raises the temperature of the system, and if it is not properly removed from the cell, it can cause membrane damage and overheating. Thermal management is thus critical for PEM fuel cell stability, efficiency, and safety. This paper investigates the potential use of NiFe2O4-water nanofluid as a novel coolant for PEM fuel cells. To determine the nanofluid thermophysical properties, an experimental study for different mass% concentrations of NiFe2O4-water nanofluid is first performed. Then, a three-dimensional CFD model is built to demonstrate the effect of nanofluid use on the thermal performance of a cooling plate. Simulation results show that replacing water with 0.5% NiFe2O4 nanofluid improves temperature uniformity by 11.97%. Furthermore, nanofluid cooling reduces maximum surface temperature by up to 0.75 degrees C while increasing pressure drop by 5.6%, implying higher pumping power.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved
Investigating Hidden Flexibilities Provided by Power-to-X Considering Grid Support Strategies
No full textHighly volatile nature of renewable energy sources (RES) has increased the demand for flexibility in electrical power systems. Electrification of the industry with power-to-X (PtX) technologies is one of the most promising ways to increase energy system flexibility since industry accounts for the largest share of the world’s total energy demand. However, flexibilities provided by power-to-X models can be concealed in the simulation results due to modelling approximations. Therefore, PtX modelling must be analyzed with respect to the requirements of flexibility analysis. Additionally, the planning and operation of such multi-energy system (MES) needs to be coordinated to use the available resources (RES & PtX) optimally. Thus, a comprehensive energy management approach must be provided for MES.This study investigates the impact of model fidelity of PtX devices in flexibility analysis. Additionally, impact of hierarchical energy management system to optimally control the flexibility dispatch is investigated. First, a realistic case study is developed for multi-energy system to investigate energy system flexibility. Secondly, power-to-gas and power-to-heat models are developed in OpenModelica, and the effect of operational temperature simplifications of PtX models on flexibility analysis is investigated. Lastly, using co-simulation, PtX models are combined with Pandapower optimal power flow solver for the optimal deployment of flexibility.The findings of this study have provided a deeper insight into multi-energy system flexibility. The investigation of hidden flexibility has revealed that precision of flexibility analysis is bounded by the efficiency characterization of PtX, and correct efficiency characterization of PtX highly depends on operating temperature conditions. The study also shown that, a comprehensive control approach can be achieved by agent-based hierarchical energy management system and this new understanding may help to improve predictions for the optimum operation point of MES.Electrical Engineering | Electrical Power Engineerin
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