Phase separation in a boson-fermion mixture of Lithium atoms

We use a semiclassical three-fluid model to analyze the conditions for spatial phase separation in a mixture of fermionic Li-6 and a (stable) Bose-Einstein condensate of Li-7 atoms under cylindrical harmonic confinement, both at zero and finite temperature. We show that with the parameters of the Paris experiment [F. Schrek et al., Phys. Rev. Lett. 87 080403 (2001)] an increase of the boson-fermion scattering length by a factor five would be sufficient to enter the phase-separated regime. We give examples of configurations for the density profiles in phase separation and estimate that the transition should persist at temperatures typical of current experiments. For higher values of the boson-fermion coupling we also find a new phase separation between the fermions and the bosonic thermal cloud at finite temperature.Comment: 8 pages, 4 figures, new version of Fig. 4 and typos correcte

Molecular Signal Modeling of a Partially Counting Absorbing Spherical Receiver

To communicate at the nanoscale, researchers have proposed molecular communication as an energy-efficient solution. The drawback to this solution is that the histogram of the molecules' hitting times, which constitute the molecular signal at the receiver, has a heavy tail. Reducing the effects of this heavy tail, inter-symbol interference (ISI), has been the focus of most prior research. In this paper, a novel way of decreasing the ISI by defining a counting region on the spherical receiver's surface facing towards the transmitter node is proposed. The beneficial effect comes from the fact that the molecules received from the back lobe of the receiver are more likely to be coming through longer paths that contribute to ISI. In order to justify this idea, the joint distribution of the arrival molecules with respect to angle and time is derived. Using this distribution, the channel model function is approximated for the proposed system, i.e., the partially counting absorbing spherical receiver. After validating the channel model function, the characteristics of the molecular signal are investigated and improved performance is presented. Moreover, the optimal counting region in terms of bit error rate is found analytically.Comment: submitted to Transactions on Communication

Structure and stability of quasi-two-dimensional boson-fermion mixtures with vortex-antivortex superposed states

We investigate the equilibrium properties of a quasi-two-dimensional degenerate boson-fermion mixture (DBFM) with a bosonic vortex-antivortex superposed state (VAVSS) using a quantum-hydrodynamic model. We show that, depending on the choice of parameters, the DBFM with a VAVSS can exhibit rich phase structures. For repulsive boson-fermion (BF) interaction, the Bose-Einstein condensate (BEC) may constitute a petal-shaped "core" inside the honeycomb-like fermionic component, or a ring-shaped joint "shell" around the onion-like fermionic cloud, or multiple segregated "islands" embedded in the disc-shaped Fermi gas. For attractive BF interaction just below the threshold for collapse, an almost complete mixing between the bosonic and fermionic components is formed, where the fermionic component tends to mimic a bosonic VAVSS. The influence of an anharmonic trap on the density distributions of the DBFM with a bosonic VAVSS is discussed. In addition, a stability region for different cases of DBFM (without vortex, with a bosonic vortex, and with a bosonic VAVSS) with specific parameters is given.Comment: 8 pages,5 figure

SPATIO-TEMPORAL ANALYSIS OF THE EFFECTS OF URBAN GROWTH ON URBAN HEAT ISLAND: CASE OF KONYA, TURKIYE

The increase in impermeable surfaces within the urban areas contributes to local and regional-scale climate changes. This phenomenon, called "Urban Heat Island," is observed as the temperature in urban areas is higher than rural areas and natural landscape areas on the urban fringe. In recent years, advances in remote sensing and geographic information system technologies have enabled the urban heat island effect to be determined more quickly, economically, and accurately. In this study, the rapidly increasing urbanization in Konya, Türkiye and the resulting urban heat island effect have been analyzed. The study consists of four steps. In the first step, land surface temperatures for 1990 and 2022 of Konya city center were determined using the thermal band of Landsat-5 TM and Landsat-8 OLI satellite images. Then, satellite images were classified using the maximum likelihood method to determine land use and land cover in Konya. The effects of land use types and urban growth on urban heat island were examined. The Normalized Difference Vegetation Index (NDVI) and Normalized Difference Built-Up Index (NDBI) analyses were examined the statistical relationships between land surface temperature. The last step, the urban heat island effects of different types of regions in the city center of Konya were determined based on their urban form, texture, structure, landscape, and planning strategy. As a result of the study, measures that can be taken especially in spatial planning and design policies have been identified to reduce and prevent the urban heat island in Konya

Diffusiophoretic Behavior of Polyelectrolyte-Coated Particles

Diffusiophoresis, the movement of particles under a solute concentration gradient, has practical implications in a number of applications, such as particle sorting, focusing, and sensing. For diffusiophoresis in an electrolyte solution, the particle velocity is described by the electrolyte relative concentration gradient and the diffusiophoretic mobility of the particle. The electrolyte concentration, which typically varies throughout the system in space and time, can also influence the zeta potential of particles in space and time. This variation affects the diffusiophoretic behavior, especially when the zeta potential is highly dependent on the electrolyte concentration. In this work, we show that adsorbing a single bilayer (or 4 bilayers) of a polyelectrolyte pair (PDADMAC/PSS) on the surface of microparticles resulted in effectively constant zeta potential values with respect to salt concentration throughout the experimental range of salt concentrations. This allowed a constant potential model for diffusiophoretic transport to describe the experimental observations, which was not the case for uncoated particles in the same electrolyte system. This work highlights the use of simple polyelectrolyte pairs to tune the zeta potential and maintain constant values for precise control of diffusiophoretic transport

Ege Üniverstesi Tıp Fakültesi Hastanesi Güneşli Sıcak Su Sisteminin Bilgisayarlı Simülasyonu

ABSTRACT Nowadays it is essential to use some other new sources of energy such as solar energy to produce energy. Although the clime of Türkiye is better than the European countries the solar energy is used less in our country. In this study; Basıc programmes have been developed to get the numeric values of the productivity of heating system with solar energy. By comparing the graphics, the results shows the possibility of comparision between the classic energies and the accomoditition arround İzmir and industrial types of usage. Preparing the programmes for computerized simulation the alternative system research has been suggested. By means of this programme the useful efficient of energy monthly or annually, according to the number of collectors, differences of types, the usage of one or two tanks, the different absorbing values of collector liquid, and the difference of hugeness of a tank for a collector. It has been produced and shown by a grafic.Bu çalışmada, Ege Üniversitesi Güneş Enerjisi Enstitüsü tarafından geliştirilerek Ege Üniversitesi Tıp Fakültesi hastanesi beşinci kısım binalarına uygulanan güneşli sıcak su sisteminin Bilgisayarlı simulasyonu için Basıc programlama dilinde, bilgisayar programı hazırlanarak, alternatif sistem araştırılmıştır. Programın yardımı ile güneşli su ısıtma sistemlerinin verimliliği, aylık ve yıllık faydalı enerji verimliliği; tek ya da çift depo kullanımına göre, elde edilerek grafik ile gösterilmiştir

Türkiye'de Perakende Sektöründe Analitik Hiyerarşik Süreç Yaklaşımıyla Tedarikçi Performans Değerlendirmesi

Artan rekabet kosullarında, isletmelerin tedarik zincirlerinin en önemli halkalarından biri olan tedarikçilerini değerlendirme ve seçme yöntemleri büyük önem kazanmıstır. Doğası gereği "çok amaçlı" bir karar verme problemi olan tedarikçi seçiminde çözüme giderken, "çoklu kritere" göre değerlendirme yapabilen yöntemler öne çıkmaktadır. Saaty (1980) tarafından gelistirilen Analitik Hiyerarsik Süreç (AHS), sistematik ve kolay uygulanabilir yapısıyla bu problem için etkin bir çözüm yöntemi önermektedir. Bu çalısmada, ulusal bir perakende zincirinin tedarikçi performans değerlendirme ve seçim sistemi AHS yöntemiyle tasarlanmıstır. Älk olarak firma yöneticileriyle, perakende sektörüne özgü performans kriterleri ve bu kriterlerin önem dereceleri belirlenmistir. Belirlenen kriterlere, AHS yöntemi uygulanarak tedarikçi değerlendirme ve puanlaması yapılmıstır. Yapılan puanlamalar sonucunda tedarikçi değerlendirmede kullanılabilecek optimum kriterler ve ele alınan tedarikçilere iliskin değerlendirme tablosu ortaya konmustur. In increasing competitive conditions, supplier evaluation and selection methodologies which constitute most important part of the supply chain of the corporations gained big importance. While solving supplier selection problem which is multi objective by its nature, methodologies which allow "multi-criteria" evaluation are powerful. Analytical Hierarchy Process (AHP) which is developed by Saaty (1980), proposes an efficient, systematic and simply applicable solution methodology. In this study, the performance evaluation and selection methodology of a nation-wide retail company are designed with AHP. First of all, retail specific performance criteria and the importance of these criteria are determined. AHP methodology applied with these criteria and supplier evalutaion and rating are made. After rating, optimum criteria which are suitable for supplier evaluation and assesment table for suppliers discussed are provided given

Verimliliğin Genel Performans Üzerindeki

ABSTRACT There are strong relationship between measuring of performance systems and real performance of firm ıf the measuring criteria one good for purpose of firm, it will be succesful in order to reflect the real performance in the same degree.In this study prodoctivity criterion, production system of West Mechain Industry (WMI) and "Model of Riggs" which is one of the measuring systems of performance were examined. After that, it was applied to production systems of WMI and general performance of WMI were determined.On the other hand, performance of productivity was examined and results determined by using date belonged to May-October 1997 period were compared with result of application of Riggs Model.As a result, it was determined that, productivity criterion did not reflect general performance of firm completely and show any increase, but general performance showed increasing tendency.İşletmelerin performans ölçme sistemleri ile gerçek performansları arasında güçlü bir bağ vardır. Ölçme kriterleri ne kadar şirket amaçlarına uygun olursa, gerçek performansını yansıtmasında da o derece başarılı olacaktır. Bu çalışmada; verimlilik ölçütü ile birlikte, Batı Makina Kalıp Sanayi A.Ş. (BMS) üretim sistemi ve performans ölçüm sistemlerinden "Riggs Modeli" teorik olarak incelenerek, BMS üretim sistemine uygulanmış ve BMS' nin genel performansı değerlendirilmiştir. Çalışmada ayrıca, BMS' nin verimlilik performansı incelenmiş, Mayıs-Ekim 1997 dönemine ait veriler kullanılarak elde edilen sonuçlar Riggs modeli uygulamasının sonuçları ile karşılaştırılmıştır. Sonuç olarak verimlilik kriterinin işletmenin genel performansını tam olarak yansıtmadığı ve gelişme göstermediği, ancak genel performansının giderek artan bir eğilim gösterdiği tespit edilmiştir

Performance Evaluation of a Passively-Aerated Plastic-Wrapped Composting System Designed for Emergency Disposal of Swine Mortalities

Monitoring of a passively-aerated plastic-wrapped mortality composting system designed for emergency disposal of diseased swine highlighted the importance of the physical characteristics of materials used to envelop the carcasses. Inadequate moisture was a problem when using envelope materials such as ground cornstalks or straw having low density and high air-filled porosity. High O2 concentrations throughout these materials, and significantly higher moisture levels in the top layers than in the materials surrounding the carcasses, suggested significant air movement and transport of carcass moisture away from the carcasses, resulting in carcass desiccation and incomplete decay. Although internal temperatures and moisture levels in test units constructed with corn silage were much more favorable than in those constructed with cornstalks or straw, less carcass decomposition occurred. Settling and compaction, resulting in high bulk density and low air-filled porosity, caused low O2 concentrations that appeared to impair carcass decay in the silage test units