bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new superior electronic properties Si allotrope for power electronic device applications
Authors: Wang Yulong , Duan Baoxing , Yang Yintang 
Published: February 2024

Abstract
A new I−4 space group silicon allotrope is proposed in this paper. The electronics properties, mechanical properties and Ag(100)/I4Si(100) interface properties are studied using first principle calculations method. The results of the phonon show that I−4 Si is dynamically stable. Elastic constants reveal I−4 Si is dynamical stable. Electronics properties calculations reveal that the CBM and VBM of I−4 Si are at X and M point, which indicates that I−4 Si is an indirect band gap semiconductor with a high band gap of 1.95 eV. To satisfy the demands for fabricating electronic devices, the N-type doping, P-type doping and Ohmic contact are studied, too. The fermi energy level of N-type and P-type I−4 Si move into conduction band and valence band, respectively. The Schottky barrier of Ag/I-4 interface is 0.65 eV. Meanwhile, the current-voltage curve becomes highly symmetric, suggesting an Ohmic behavior of the Ag(100)/I4Si(100) interface. Critical breakdown field calculations results show that the critical breakdown field of I−4 Si is 9.05 × 105 V cm−1, which is 3.02 times that of the diamond Si. Because band gap and critical breakdown field of I-4 Si are much greater than that of diamond Si, I-4 Si is potential electronic semiconductor material. Thus, I−4 Si can be applied in the field of modern power electronic device applications due to its superior electronic properties.
Gravitational wave footprints from Higgs-portal scalegenesis with multiple dark chiral scalars*
Authors: Zhang 张 He-Xu 贺旭 , Matsuzaki Shinya , Ishida Hiroyuki 
Published: February 2024

Abstract
We discuss the gravitational wave (GW) spectra predicted from the electroweak scalegenesis of the Higgs portal type with a large number of dark chiral flavors, which many flavor QCD would underlie and give the dynamical explanation of the negative Higgs portal coupling required to trigger the electroweak symmetry breaking. We employ the linear-sigma model as the low-energy description of dark many flavor QCD and show that the model undergoes ultra-supercooling due to the produced strong first-order thermal phase transition along the (approximately realized) flat direction based on the Gildener-Weinberg mechanism. Passing through evaluation of the bubble nucleation/percolation, we address the reheating and relaxation processes, which are generically non-thermal and nonadiabatic. Parametrizing the reheating epoch in terms of the e-folding number, we propose proper formulae for the redshift effects on the GW frequencies and signal spectra. It then turns out that the ultra-supercooling predicted from the Higgs-portal scalegenesis generically yields none of GW signals with the frequencies as low as nano Hz, unless the released latent heat is transported into another sector other than reheating the universe. Instead, models of this class prefer to give the higher frequency signals and still keeps the future prospected detection sensitivity, like at LISA, BBO, and DECIGO, etc. We also find that with large flavors in the dark sector, the GW signals are made further smaller and the peak frequencies higher. Characteristic phenomenological consequences related to the multiple chiral scalars include the prediction of dark pions with the mass much less than TeV scale, which is also briefly addressed.
Cross sections for 14 MeV neutron interaction with lutetium isotopes and their theoretical excitation functions*
Authors: Song 宋 Yueli 月丽 , Zhou 周 Fengqun 丰群 , Li 李 Yong 勇 , Zhang 张 Xiaopeng 晓朋 , Ji 姬 Pengfei 鹏飞 , Sun 孙 Xiaojun 小军 
Published: February 2024

Abstract
The cross-sections for the 175Lu(n,p)175Yb, 175Lu(n,α)172Tm, 176Lu(n,α)173Tm, 175Lu(n,2n)174mLu, and 175Lu(n,2n)174gLu reactions at 13.57, 14.03 14.62, and 14.86 MeV neutron energies were measured using an activation technique. The theoretical excitation functions of these reactions were calculated using the Talys-1.95 code. The reaction cross-section data experimentally obtained were analyzed and compared with experimental data reported in the literature, data from five major evaluated nuclear data libraries of IAEA, and theoretical values based on Talys-1.95. The data obtained at some neutron energies agree with some of the data reported in the literature and theoretical values based on Talys-1.95. The consistency of the theoretical curves of excitation functions based on Talys-1.95 with the data obtained in this study and those reported in the literature is higher than that of the evaluation curves of excitation functions for the 175Lu(n,p)175Yb, 175Lu(n,α)172 Tm, and 176Lu(n,α)173Tm reactions. This study is helpful because it provides new evaluated reaction cross-section data on lutetium (which is a fusion reactor material), improves the quality of neutron-induced reaction cross section data libraries, and advances the research on related applications.
An experimental study of pedestrian bidirectional flow through bottlenecks
Authors: Jia Xinmiao , Jiang Nan , Zhang Ping , Li Maoyu , Yu Hanchen , Ju Xiaoyu , Yang Lizhong 
Published: February 2024

Abstract
Pedestrian flow passing through bottlenecks is complex, particularly for opposite movement in a room with a single doorway. These bidirectional flows would always cause congestion and further reduce traffic efficiency so the ‘Disembarking precedes embarking’ rule is widely used in the actual management of public spaces. However, the impact of the imbalance of the bidirectional movement of pedestrian numbers on the pedestrian capacity and throughput at the bottleneck still needs further exploration. Therefore, this study investigates the effects of the ratio r of pedestrians leaving the room to the total number of participants and the bottleneck widths (1.2, 1.6 and 2.0 m) on the movement behavior of pedestrians in bidirectional flow and the efficiency of passing through by conducting controlled experiments where pedestrian trajectories, speed, density, flow and time headway are analyzed. Results indicate that the bottleneck width and the pedestrian flow rate are linearly related, whereas the r and flow have a nonlinear relationship. Specifically, r = 10% is the optimal value for improving the pedestrian traffic efficiency at the bottleneck, which is even better than the unidirectional scenario. The most significant density in the measuring area is at r = 30%, corresponding to the greatest probability of clogging. The pedestrian density within the room influences the flow rate at the bottleneck, thereby indicating that wider doors are not always better from a design perspective. The findings presented in this paper can provide actual data to validate bidirectional pedestrian flow simulation models and theoretical support for pedestrian facility and crowd management optimization.
Overlap structure and free energy fluctuations in short-range spin glasses
Authors: Newman C M , Stein D L 
Published: February 2024

Abstract
We investigate scenarios in which the low-temperature phase of short-range spin glasses comprises thermodynamic states which are nontrivial mixtures of multiple incongruent pure state pairs. We construct a new kind of metastate supported on Gibbs states whose edge overlap values with a reference state fall within a specified range. Using this metastate we show that, in any dimension, the variance of free energy difference fluctuations between pure states within a single mixed Gibbs state with multiple edge overlap values diverges linearly with the volume. We discuss some implications of these results.
Vegetation types and habitats with participation of plant species – local endemics to the marble part of Northern Pirin Mts., Bulgaria
Authors: Nacheva Veradina , Tzonev Rossen , Pachedjieva Kalina , Kolchagov Rumen , Gussev Chavdar , Pavlova Dolja 
Published: February 2024

Abstract
This study was carried out in the carbonate (marble) part of North Pirin Mts. Its upper parts are declared protected area of National Park category according to the Bulgarian Protected Areas Act. It is also a NATURA 2000 protected zone under the Habitats Directive, and a natural UNESCO World Heritage Site. The main reason for the conservation of this territory is the exceptional concentration of rare, relict and endemic plant species, its specific flora, vegetation and fauna. Subject of the study are the plant communities and habitats, with participation of 8 local endemic plant taxa, such as Cyanus achtarovii, Oxytropis kozhuharovii, O. urumovii, Odontarrhena orbelica, Alyssum pirinicum, Veronica kellereri, Brassica nivalis subsp. jordanoffii and Arabis ferdinandi-coburgii. The plant communities were studied according to the classical Braun-Blanquet’s approach by sampling the phytocoenoses, where the local endemics participate. The major syntaxa to which these communities belong, were determined. The plant communities with the participation of local endemics were also referred to lower units according to EUNIS habitats classification. The study found that most of the studied endemic species occur in various vegetation types and exhibit relatively wide ecological flexibility, despite inhabiting restricted area. The main reason for this is the comparative uniformity of the high mountain marble relief. This study also highlights the high conservation value of the vegetation cover and habitat diversity of the carbonate alpine and subalpine vegetation belts of Northern Pirin Mts., as a habitat for numerous endemic and relict plant species.
An update to the genus Bolboschoenus in Bulgaria - species diversity, distribution and phytosociological affinities
Authors: Kunev G 
Published: February 2024

Abstract
The current study presents new data on the distribution of the representatives of the genus Bolboschoenus in Bulgaria and gives a brief description of their communities. It is based on revision of herbarium materials, field observations and phytosociological samples. Morphological characteristics and ecological traits of the studied taxa are commented. A synopsis of all collected chorological information is attached.
Comparison of the zooplankton-based RCC to Carlson’s trophic state indices and water quality parameters
Authors: Stanachkova Marieta , Dashinov Dimitriy , Traykov Ivan 
Published: February 2024

Abstract
Zooplankton is not included as a biological quality element, even though it is a key component of pelagic food webs. The data on zooplankton community structure can be used to evaluate the trophic state of lakes through an RCC Index, based on quantitative proportions between the main zooplankton groups. As previous investigations have related the index only to the Secchi disc transparency, the aim of this study was to compare the Index to a set of water quality parameters and trophic state indices. Two sandpit lakes with contrasting characteristics were selected as model lakes for the study. A total of 57 samples were collected simultaneously with the physicochemical water quality parameters between 2016 and 2020. Carlson’s trophic state indices were used to assess the trophic state of the lakes. Pearson correlation coefficient and Principal Component Analysis were used to assess the observed correlations between the measured parameters and to distinguish what factors regulate zooplankton community structure. Overall, 86 zooplankton taxa were identified. RCC Index ranged from 2 in the small sandpit lake to 87 in the big sandpit lake. A highly significant negative correlation was found between the RCC Index and the values of TP and COD. The results complement the arguments for the inclusion of zooplankton as a BQE for the assessment of the status of lakes.
Water Safety Plan: A case study from Sofia, Bulgaria
Authors: Aleksova M , Schneider I 
Published: February 2024

Abstract
According to Directive 2184/2020 on the quality of water intended for human consumption and World Health Organization (WHO) best practice, the Water Safety Plan (WSP) includes a review of the whole water supply chain – from protection of the water source, through water abstraction, transportation, treatment, storage and distribution to the end user. Risk management is based on the introduction of corrective, control and preventive measures, as well as subsequent validation of the measures taken and monitoring of their implementation according to the Deming cycle. The purpose of the current study is to review individual components of the WSP implementation and the effectiveness of WSP developed and implemented by Sofiyska voda JSC (SV) - the water supplier of Sofia, the capital of Bulgaria. The article presents the overall approach followed by the water supply operator, including the system review, risk identification and assessment, mitigation barriers, process control through critical control points (CCPs), review and verification of all risk management measures taken.
Effectiveness of point-of-use (POU) filter system for removal of contaminants from water
Authors: Manoleva N P , Bankova E K , Traykov I T 
Published: February 2024

Abstract
Groundwater supplies most of the drinking water in the small settlements in the Danubian plain region of Bulgaria. The region is mostly agricultural, leading to chemical pollution, mostly with nitrogen, of the shallow groundwater. Direct health concerns, linked to nitrates contamination of water, determine the increased popularity of drinking water point-of-use (POU) filtration pitchers. The objective of this study was to evaluate the effectiveness of a commercial pitcher filtration system in removing select pollutants, such as metal ions, namely, copper and iron, nitrate nitrogen, and suspended solids (algal culture of Monoraphidium contortum) from augmented tap water. In addition, we have studied the effects on electrical conductivity and pH of water. The POU system of choice was a widely used brand name in Bulgaria, providing cartridges that fit most of the European pitcher filter brands. We have evaluated the performance of the filters at three different exploitation intervals – pre-washed new filter (0%), 50%, and 100% of the exploitation capacity set according to manufacturers’ claims of recommended volume of water, as well as at different contact times between the water and the filter media. The results indicate that the efficiency of the filters diminishes with aging and increases with increasing contact time – multiple filtrations.
The efficiency in terms of electrical conductivity and amount of iron decreases proportionally with filter age, and in terms of phosphates, the maximum effect is observed in filters at 50% capacity. Water filtration reduced water conductivity by 12% in a single filtration and stabilized the pH values towards the neutral range. The effect on pH values is inversely proportional to the buffering capacity of the water. The filters removed 85–98% of copper ions and 20% of iron ions. Nitrate removal efficiency averages 40% and doubling the contact time increases the efficiency to 70%. The efficiency of removing suspended solids is on average 17%, mainly due to the small size of the particles.
Overall, the POU systems are an effective way to purify water at home. The filter cartridges effectively reduce contaminants, such as metals and nitrates, which are particularly problematic in areas supplied by groundwater sources.
Effect of different lanthanide ions on the catalytic activation of peroxymonosulfate with lanthanide metal-organic frameworks (Ln-MOFs) with terephthalic acid
Authors: Elenkova D. K. , Gagashev D. A. , Encheva E. D. , Tsvetkov M. P. 
Published: February 2024

Abstract
Ln-MOFs with four different Ln-ions (La, Ce, Gd, Tb) and terephthalic acid (H2BDC) were synthesised by solvothermal method. The crystals structure was confirmed by powder XRD and infrared spectroscopy (IR) corresponding to [Ln2(BDC)2(H2O)4]∞ and microstructural information of all samples was extracted by applying Rietveld refinement. By scanning electron microscopy (SEM) the morphology of the samples was revealed. First time applying Ln-MOFs for the catalytic activation of peroxymonosulfate (PMS) demonstrated their potential application as catalysts in a Fenton-like reaction for water purification from the antibiotic tetracycline hydrochloride (TCH). For the best performing Ce-MOF degradation of TCH reached 80% that’s why additional experiment for determination of activation energy and the mechanism of the catalytic reaction were performed. The stability of the catalyst was also confirmed by powder XRD after the reaction.
Hepatoprotective effect of the flavonoid fustin in a rat model of paracetamol-induced acute liver damage
Authors: Salbashian M , Stefanova N , Tzaneva M , Pavlov D , Novakovic M , Tesevic V , Georgieva A , Eftimov M , Reyzov M , Nikolova M , Valcheva-Kuzmanova S 
Published: February 2024

Abstract
Paracetamol (PCM)-induced toxicity is a well-established pharmacological model. Cotinus coggygria is a medicinal plant rich in polyphenols, including the flavonoid fustin. The aim of the present study was to evaluate the effects of the flavonoid fustin isolated from Cotinus coggygria heartwood in a model of PCM-induced liver damage. Male Wistar rats (n=48) were allocated to four groups: Control, PCM, F5+PCM, F10+PCM. The rodents were treated daily orally for nine consecutive days as follows: groups F5+PCM and F10+PCM – with fustin (suspended in a vehicle) at doses of 5 and 10 mg/kg, respectively; groups Control and PCM – with the vehicle. PCM was injected intraperitoneally (1.0 g/kg) on day 7. At the end of the experiment, serum and liver samples were prepared. PCM caused a severe liver damage confirmed by histopathological, immunohistochemical and biochemical indices. Compared to PCM group, in F5+PCM and F10+PCM groups, the hepatic necrosis, steatosis, ballooning degeneration, inflammation and expression of NF-κB were significantly reduced. Fustin treatment resulted in a significant reduction of serum activities of alanine aminotransferase and gamma-glutamyl transferase to levels that did not differ from the control values. The present study demonstrated a hepatoprotective effect of the flavonoid fustin in a rat model of acute paracetamol-induced toxicity.
Biosensor-based serological assay for diagnosing Helicobacter pylori infection
Authors: Kolev P , Hikova E , Kisov H , Dyankov G 
Published: February 2024

Abstract

Helicobacter pylori causes the most common bacterial infection involving 50% of the global population. According to the World Health Organization H. pylori infection contributes to approximately 75% of the stomach cancer cases and 5.5% of all types of cancer. Therefore, timely diagnosis of the infection is highly desirable. Serological assays are widely performed for diagnosing H. pylori infection, the most frequently used one being ELISA. In the present study we showed that a serological assay can also be carried out using a biosensor based on Surface Plasmon Resonance (SPR). Unlike our previous studies where we used amplitude detection of the binding reactions, here we applied phase-sensitive detection. It was performed with a the channeled spectroscopic ellipsometer, which allowed fast measurement with high sensitivity. Thus, the detection limit achieved was more than two times lower than that of the amplitude detection. In terms of CFU, phase detection was sensitive even at 200 CFU, while amplitude detection was applicable at 3000 CFU.
Ultrasonic non-destructive evaluation study of molecular diffusion bonding of thin copper-aluminum electrode sheets
Authors: Li Shengtao , Hou Huaishu , Yun Han , Li Jinhao 
Published: February 2024

Abstract
The weld quality of copper and aluminum thin electrode sheets in molecular diffusion bonding was non-destructively evaluated using ultrasonic resonance techniques. During the welding process, the intermediate layer material nickel diffuses into the molecules of both the copper sheet and aluminum sheet, resulting in the formation of a solid solution phase layer. This leads to a 5-layer structure in the welded body. If there are defects in this solid solution phase layer, it can cause mutations in the ultrasonic resonance signals within the weld body. In order to characterize the weld quality between copper and aluminum sheets, an acoustic attenuation coefficient was introduced. The ultrasonic resonance signals within the weld body of copper and aluminum thin electrode sheets were analyzed under four different welding states. Experimental testing revealed significant differences in acoustic attenuation coefficients among these different welding states. A smaller acoustic attenuation coefficient indicates better welding quality. Therefore, by setting a reasonable threshold for this coefficient, it is possible to effectively evaluate the welding quality of molecular diffusion bonding between copper and aluminum thin electrode sheets.
Analyzing land use land cover (LULC) changes induced by the run-of river project and respondent survey: a case of Ghazi Barotha Hydropower Project on Indus River, Pakistan
Authors: Inam Ullah Ehsan , Ahmad Shakil , Khokhar Muhammad Fahim , Khayyam Umer , Azmat Muhammad , Arshad Muhammad , ur Rehman Qaiser Faizan 
Published: February 2024

Abstract
Land use land cover (LULC) change determination caused by development projects is always mandatory as land is the major source of local livelihoods and regional economy. Worldwide, very limited studies have been conducted to determine LULC changes caused by run-of-the-river projects, which are generally considered safe due to their design. Present study used Google Earth Engine (GEE) to examine the LULC changes caused by Ghazi Barotha Hydropower Project (GBHP), which is a run-of-the-river project, built in 2002 on Indus River in Pakistan. The project diverts river water from Ghazi barrage, for a 6,600 GWh annual power production, through an open concrete power channel of 100 m width and 9 m depth. Field surveys were carried out to assess respondents’ opinions about LULC changes and their major causes. LULC determination was carried out from 1990–2020 through processing Landsat images in GEE, and Random Forest (RF) machine learning technique was used for supervised classification of the study area. 384 respondents were consulted during the field survey and their responses were collected using semi-structured self-administered proformas. Results showed that after functioning, GBHP caused major LULC changes in project downstream areas from 2002–2010, as there was a significant decrease in area under agriculture by 29.10% and 47%, during summer and winter seasons respectively. The trend was concurrent with a decrease in area under water and was also followed by a marked increase in area under vegetation and baresoil. However, from 2010–2020, agriculture area again increased by 75.61% and 84.53% in summer and winter seasons respectively, as compared to 2002–2010. Respondents during the field survey revealed that agriculture reduction from 2002–2010 was due to water scarcity caused by GBHP; also leading to vegetation and baresoil increase. Recovery of agriculture from 2010–2020 was attributed to groundwater development intervention, better seeds, and farmers’ capacity building.