Alternating, private alternating, and quantum alternating realtime automata

We present new results on realtime alternating, private alternating, and quantum alternating automaton models. Firstly, we show that the emptiness problem for alternating one-counter automata on unary alphabets is undecidable. Then, we present two equivalent definitions of realtime private alternating finite automata (PAFAs). We show that the emptiness problem is undecidable for PAFAs. Furthermore, PAFAs can recognize some nonregular unary languages, including the unary squares language, which seems to be difficult even for some classical counter automata with two-way input. Regarding quantum finite automata (QFAs), we show that the emptiness problem is undecidable both for universal QFAs on general alphabets, and for alternating QFAs with two alternations on unary alphabets. On the other hand, the same problem is decidable for nondeterministic QFAs on general alphabets. We also show that the unary squares language is recognized by alternating QFAs with two alternations

Optimization of finite-range effective interaction for in-medium cross sections

In order to incorporate the finite range effect into effective interactions, a modification of the Skyrme force by introducing a cut-off factor for high momentum transfers is proposed. The parameters of the cut-off factor are determined by fitting the microscopic in-medium cross-sections of Li and Machleidt over a wide range of energy and nuclear density. Results for the SkM* and SLy4 forces are presented

Quantal description of nucleon exchange in a stochastic mean-field approach

The nucleon exchange mechanism is investigated in central collisions of symmetric heavy ions in the basis of the stochastic mean-field approach. Quantal diffusion coefficients for nucleon exchange are calculated by including non-Markovian effects and shell structure. Variances of fragment mass distributions are calculated in central collisions of Ca-40 + Ca-40, Ca-48 + Ca-48, and N-56 i+ Ni-56 systems

Multi-criteria evaluation of hydrogen and natural gas fuelled power plant technologies

This paper evaluates nine types of electrical energy generation options with regard to seven criteria. The options use natural gas or hydrogen as a fuel. The Analytic Hierarchy Process was used to perform the evaluation, which allows decision-making when single or multiple criteria are considered. The options that were evaluated are the hydrogen combustion turbine, the hydrogen internal combustion engine, the hydrogen fuelled phosphoric acid fuel cell, the hydrogen fuelled solid oxide fuel cell, the natural gas fuelled phosphoric acid fuel cell, the natural gas fuelled solid oxide fuel cell, the natural gas turbine, the natural gas combined cycle and the natural gas internal combustion engine. The criteria used for the evaluation are CO2 emissions, NOX emissions, efficiency, capital cost, operation and maintenance costs, service life and produced electricity cost. A total of 19 scenarios were studied. In 15 of these scenarios, the hydrogen turbine ranked first and proved to be the most preferred electricity production technology. However since the hydrogen combustion turbine is still under research, the most preferred power generation technology which is available nowadays proved to be the natural gas combined cycle which ranked first in five scenarios and second in eight. The last in ranking electricity production technology proved to be the natural gas fuelled phosphoric acid fuel cell, which ranked in the last position in 13 scenarios

Male-female differences in thoracic aortic diameters at presentation of acute type A aortic dissection

Background: Acute type A aortic dissection (ATAAD) is a highly lethal event, associated with aortic dilatation. It is not well known if patient height, weight or sex impact the thoracic aortic diameter (TAA) at ATAAD. The study aim was to identify male–female differences in TAA at ATAAD presentation. Methods: This retrospective cross-sectional study analysed all adult patients who presented with ATAAD between 2007 and 2017 in two tertiary care centres and underwent contrast enhanced computed tomography (CTA) before surgery. Absolute aortic diameters were measured at the sinus of Valsalva (SoV), ascending (AA) and descending thoracic aorta (DA) using double oblique reconstruction, and indexed for body surface area (ASI) and height (AHI). Z-scores were calculated using the Campens formula. Results: In total, 59 % (181/308) of ATAAD patients had CT-scans eligible for measurements, with 82 female and 99 male patients. Females were significantly older than males (65.5 ± 12.4 years versus 60.3 ± 2.3, p = 0.024). Female patients had larger absolute AA diameters than male patients (51.0 mm [47.0–57.0] versus 49.0 mm [45.0–53.0], p = 0.023), and larger ASI and AHI at all three levels. Z-scores for the SoV and AA were significantly higher for female patients (2.99 ± 1.66 versus 1.34 ± 1.77, p &lt; 0.001 and 5.27 [4.38–6.26] versus 4.06 [3.14–5.02], p &lt; 0.001). After adjustment for important clinical factors, female sex remained associated with greater maximal TAA (p = 0.019). Conclusion: Female ATAAD patients had larger absolute ascending aortic diameters than males, implying a distinct timing in disease presentation or selection bias. Translational studies on the aortic wall and studies on growth patterns should further elucidate these sex differences.</p

Ağır-iyon reaksiyonlarının stokastik ortalama-alan kuramı çerçevesinde incelenmesi

TÜBİTAK MFAG15.10.2015Bu projede, ağır-iyon derin-inelastik çarpışmalarında mermi ve hedef çekirdekler arasında nükleon alış-verişi ile ilgili transport katsayıları için stokastik ortalama- alan kuramı (SOA) çerçevesinde yarı-klasik ve hafıza etkilerini içeren kuantal hesaplamalar yapıldı. Simetrik ve proton/nötron bakımından asimetrik sistemlerin füzyon potansiyel bariyer değerlerinin hemen altındaki enerjilerde merkezi ve merkezi olmayan çarpışmaları göz önüne alındı. Ağır-iyonların merkezi çarpışmaları için türetilen ve simetrik sistemlerde test edilen kuantum mekaniksel hesaplar, asimetrik sistemlere ve merkezi olmayan çarpışmalara genişletildi. Benzer şekilde, nükleon alışveriş difüzyon katsayısının analitik ifadeleri, simetrik ve asimetrik ağır-iyonların merkezcil olmayan çarpışmaları için hafıza etkilerini de içerecek şekilde kuantum mekaniksel olarak türetildi. Proje kapsamında, ağır-iyon derin-inelastik çarpışma sonrası ayrışan çekirdeklerin proton ve nötron difüzyon katsayıları, kütle dağılımlarının varyansları ile toplam difüzyon katsayısı ve toplam nükleon kütle dağılımının varyansı çeşitli sistemler için hesaplandı. Proje iş paketlerinde öngörülen ve aşağıdaki verilen tüm çalışmalar tamamlandı. 1) Simetrik ve nötron/proton bakımından asimetrik atom çekirdeklerinin düşük- enerjili derin-inelastik merkezcil transport katsayılarının kuantal olarak hesaplanması ve daha önce yapılan yarı-klasik hesaplarla karşılaştırılması yapıldı. 2) Simetrik ve asimetrik atom çekirdeklerinin düşük-enerjili derin-inelastik merkezcil olmayan çarpışmalarında toplu değişkenlerin tanımlanması için gerekli olan pencere dinamığının zamana bağlı Hartree-Fock programına gerekli eklemeler yapılarak, proton ve nötron alış-verişi ile ilgili difüzyon katsayılarının kuantal olarak hesaplanması, bu katsayıları kullanarak ayrışan çekirdeklerin proton ve nötron dağılımlarının ortalama değerlerinin ve varyanslarının hesaplanması yapıldı. 3) Simetrik ve nötron/proton bakımından asimetrik atom çekirdeklerinin düşük- enerjili derin-inelastik merkezcil olmayan çarpışmalarında nükleon alış- verişine dayalı transport katsayılarının kuantal olarak hesaplanması, enerji disipasyon ve salınım mekanizmasının incelenmesi yapıldı. 4) Ağır çekirdekler arası nükleon transferi için transport katsayılarının hafıza etkilerini yaklaşık olarak hesaba katarak kuantal hesaplanması için yeni bir yöntem geliştirildi. 5) Yarı-fisyon reaksiyonlarının difüzyon menizmasıyla incelenmesi hesapları yapıldı