Average Figure Research Articles

AgSbSe2 inclusions enabling high thermoelectric and mechanical performance in n-type Ag2Se-based composites

Ag2Se is a promising near-room-temperature thermoelectric material with prospective applications in solid-state cooling and waste heat recovery. To advance the practical application of Ag2Se, it is imperative yet challenging to further boost its average dimensionless figure of merit (zT) and mechanical performance. Herein, we effectively enhance the two types of performance by constructing Ag2Se/AgSbSe2 composite architectures with uniform distribution of AgSbSe2 inclusions, which was realized by sintering solution-synthesized mixtures of Ag2Se nano/micro-particles and Sb2Se3 nanorods. Particulate AgSbSe2 and as-built Ag2Se/AgSbSe2 interfaces enable intensified phonon scattering and impeded crack propagation, and refined grain size additionally contributes to optimized thermal and mechanical properties. As a result, (Ag2Se)0.98(2AgSbSe2)0.02 composite approaches a low lattice thermal conductivity of 0.15 W m–1 K–1 at 375 K and an excellent average zT of ∼0.89 between 300 and 375 K; mechanically, this composite obtains a compressive strength of 197.3 MPa, which is improved by ∼125% compared to that of Ag2Se and represents the highest value ever reported for this compound. This study sheds light on the efficacy of introducing secondary-phase particles on simultaneously boosting the thermoelectric and mechanical performance of Ag2Se.

Defect-Engineering-Stabilized AgSbTe2 with High Thermoelectric Performance.

Thermoelectric (TE) generators enable the direct and reversible conversion between heat and electricity, providing applications in both refrigeration and power generation. In the last decade, several TE materials with relatively high figures of merit (zT) have been reported in the low- and high-temperature regimes. However, there is an urgent demand for high-performance TE materials working in the mid-temperature range (400-700 K). Herein, p-type AgSbTe2 materials stabilized with S and Se co-doping are demonstrated to exhibit an outstanding maximum figure of merit (zTmax ) of 2.3 at 673 K and an average figure of merit (zTave ) of 1.59 over the wide temperature range of 300-673 K. This exceptional performance arises from an enhanced carrier density resulting from a higher concentration of silver vacancies, a vastly improved Seebeck coefficient enabled by the flattening of the valence band maximumand the inhibited formation of n-type Ag2 Te, and ahighly improved stability beyond 673 K. The optimized material is used to fabricate a single-leg device with efficiencies up to 13.3% and a unicouple TE device reaching energy conversion efficiencies up to 12.3% at a temperature difference of 370 K. These results highlight an effective strategy to engineer high-performance TE material in the mid-temperature range.

Ultrafast generation and detection of coherent acoustic phonons in SnS0.91Se0.09

The rapid growth of attention to tin sulfide (SnS) is due to its efficient application in the field of thermoelectricity, and its doping product SnS0.91Se0.09 can obtain a high average thermoelectric figure of merit (ZTave≈ 1.25). Although many efforts have been made to reveal the mechanisms associated with electron transport and heat conduction, the role of lattice vibration remains poorly understood. Here, we studied the coherent vibration dynamics in SnS0.91Se0.09 bulk single crystal by using the femtosecond two-color pump-probe optical reflectivity technique. The oscillation signal in the time domain of SnS0.91Se0.09 is considered to be an electron–phonon interaction. The coherent dynamics of longitudinal acoustic phonons in this coupling behavior is closely related to probe polarization and excitation power. The stability of oscillation frequency reveals the microscopic mechanism of phonon conduction, and further understands the lattice nonharmonic caused by electron–phonon interaction in light-induced.

Wood industry clusters and their optimal location for the efficient use of forest raw materials

World experience in the creating of clusters in different industries has shown their effectiveness. This paper investigated the resource potential for creating a cluster designed for wood processing and to process wood waste from the timber industry of the Krasnoyarsk Territory of Russia. Static indicators were assessed, representing a quantitative characteristic of forest raw material resources: total and operational reserves of wood available in the region. While studying the state and use of forest resources, significant reserves of forest resources and secondary raw materials were revealed. Main indicators of the forest industry of the region over recent years were analyzed. The main systemic issues hindering the development of the timber industry were exposed. It was concluded that the region has raw material potential and industrial infrastructure necessary for the formation and sustainable development of a cluster for processing waste from the timber industry. Analysis of the producers and harvesters of forest products’ locations revealed potential wood industry clusters, and areas suitable for cluster economic development were proposed. The average figures of the nearest neighbor were used and analyzed to examine the spatial distribution of raw material harvesters and enterprises that produce finished products with respect to transport infrastructure, staffing, and raw material availability.

MAIN AGE-RELATED CUTANEOUS CHANGES IN MEN GROUNDED ON THE RESULTS OF ULTRASONIC DIAGNOSTICS

Introduction. An extremely important task of modern medical science is to preserve the health of the population. Various age violations are found in men, such as changes in the functional activity of different systems and organs. Age-related changes have a negative influence on health state, the course of different diseases, and life quality. Materials and Methods. 120 men aged 25–64 years were examined. They were divided into four clinical groups according to the age of patients: I group – 25–34 years old, II group – 35–44 years old, III – 45–54 years old, and IV – 55–64 years old. We proposed the use of Cratal and Quercetin medications for 30 days for men from group III, and Tiocetam-Forte for 30 days for men from group IV. Ultrasound examination and dopplerography were performed. For statistical analysis, the paired Student's t-test was used. Statistical analysis was performed using STATISTICA 6.1 software. Results. The reduction in thickness of the different layers of the skin in men of older age groups was registered. Low levels of flow velocity (its maximum and average figures), as well as high resistance index and pulse activity index, were observed in males of mature age. In cases, when antioxidants, nootropics, and vasoprotectives were prescribed for prophylaxis, flow velocity (its maximum and average figures) increased in skin vessels, while resistance index and pulse activity index dеcreased. Conclusions. It was shown in the investigation that the use of antioxidants, nootropics, and vasoprotectives were effective for the prevention of skin aging and blood-flow violations in it in males of older age groups.

Isolated Vascular Rings Are Common Cardiovascular Malformations.

We investigated the prevalence of isolated vascular rings in the general population of Southern Nevada. We identified those prenatally and postnatally diagnosed with an isolated vascular ring between January 2014 and December 2021. We included only those with vascular or ligamentous structures completely encircling the trachea and esophagus. To investigate the prevalence of isolated vascular rings, we included only those with situs solitus, levocardia, and no significant intracardiac malformations. We identified 112 patients. Of the 112, 66 (59%) were female. There were approximately 211,000 total live births in Southern Nevada for the study period, for an overall prevalence of 5.3 isolated vascular rings per 10000 live births. However, for the years 2014 to 2017, the average prevalence figure was 3.5 per 10000 live births, and for the years 2018 to 2021, the average prevalence figure was 7.1 (range 6.5-8.0) per 10000 live births. Simultaneously, the prenatal detection rate rose from 66% to 86%. Isolated vascular rings are common cardiovascular malformations. As prenatal detection rates in the Southern Nevada general population approach 90%, the prevalence figures for isolated vascular rings appear to asymptote at about 7 per 10000 live births.

Engineering an atomic-level crystal lattice and electronic band structure for an extraordinarily high average thermoelectric figure of merit in n-type PbSe

Multiscale defect structures driven by interstitial Cu, off-centered Pb and Se atoms and scarce anion vacancies in the new CuxPb(Se0.8Te0.2)0.95 give a record-high average ZT among all polycrystalline n-type thermoelectric materials due to high PF.

Wideband and Efficient 256-GHz Subharmonic- Based FMCW Radar Transceiver in 130-nm SiGe BiCMOS Technology

This article proposes a fully integrated single-channel bistatic frequency-modulated continuous-wave (FMCW) radar transceiver (TRX) that operates at a center frequency of 256 GHz. The main focus of this work is to realize a wideband and efficient radar TRX that offers high resolution of target detection in the short-range FMCW radar sensing application. The radar TRX chip is designed and manufactured using the 130 nm silicon–germanium (SiGe) bipolar complementary metal-oxide-semiconductor (BiCMOS) technology which offers heterojunction bipolar transistors (HBTs) with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f_{\mathbf {T}}/f_{\mathbf {MAX}}$ </tex-math></inline-formula> of 300/500 GHz. The transmitter (TX) of the radar TRX is based on a fundamentally operated multiplier-by-8 chain architecture that offers a 3-dB bandwidth of around 65 GHz with a saturated output power of −5.4 dBm. On the other hand, the receiver (RX) is based on a subharmonic architecture that provides a conversion gain (CG) of 10.4 dB with an average noise figure (NF) of 23.5 dB. This TRX is realized with two integrated on-chip folded dipole antennas. The antenna offers high antenna gain and radiation efficiency due to the use of the selective localized backside etching (LBE) technique. This chip consumes 305 mW of power from a 3.3-V supply and occupies a silicon area of 3.3 mm2. The radar range measurement is performed in an anechoic chamber, and it shows the maximum dynamic range (DR) of around 34 dB at 1-m range of the target.

A boost of thermoelectric generation performance for polycrystalline InTe by texture modulation.

The new rising binary InTe displays advantageously high electronic conductivity and low thermal conductivity along the [110] direction, providing a high potential of texture modulation for thermoelectric performance improvement. In this work, coarse crystalline InTe material with a high degree of texture along the [110] direction was realized by the oriented crystal hot-deformation method. The coarse grains with high texture not only maintain the preferred orientation of the zone-melting crystal as far as possible, but also greatly depress the grain boundary scattering, thus leading to the highest room temperature power factor of 8.7 μW cm-1 K-1 and a high average figure of merit of 0.71 in the range of 300-623 K. Furthermore, the polycrystalline characteristic with refined grains also promotes the mechanical properties. As a result, an 8-couple thermoelectric generator module consisting of p-type InTe and commercial n-type Bi2Te2.7Se0.3 legs was successfully integrated and a high conversion efficiency of ∼5.0% under the temperature difference of 290 K was achieved, which is comparable to traditional Bi2Te3 based modules. This work not only demonstrates the potential of InTe as a power generator near room temperature, but also provides one more typical example of a texture modulation strategy beyond the traditional Bi2Te3 thermoelectrics.

Assessing the economics and finances of Artisanal and small-scale gold mining in Guyana

Artisanal and small-scale mining (ASM) is a vital source of non-farm rural income across much of the Global South, and a key provider of jobs and livelihoods in South America, Africa and Asia. Despite this importance, however, there is very little research into the economics and finances of these small (and often medium-sized) operations. This paper summarises the result of a survey of ASM gold miners in Guyana in late 2020 that delved into the costs, revenues, financing and profitability of a range of small and medium-size miners in the country, for which the industry is a vital source of foreign exchange, economic growth and employment. The results from the survey highlight a potentially lucrative sector with some operators making large profits. However average figures mask a long-tailed distribution with many miners operating at the margins of profitability or a loss. These challenges are amplified by the large capital costs associated with operating in the sector, which are compounded by the difficulties miners face accessing capital markets. Beyond the headline figures, the survey highlights the potential attractiveness of the sector in terms of wages, and also the very small share of costs relating to the use of mercury – highlighting the challenge of utilising economic policy to reduce and eliminate the use of the chemical. The results demonstrate the need to collect more economic and financial data on the sector in order to best understand how to drive change in the sector, helping to mitigate its negative social and environmental impacts, whilst maximising the economic benefits it can bring.

Uncompleted construction work in the Russian Federation: causes and remedies

Uncompleted construction work is a major issue for the sector and the economy as a whole. According to Russia’s Accounts Chamber, the current average figure for state-funded projects in Russia in this respect is 30% (as much as 70% in some regions). As a possible solution, this paper suggests using a system of surveys of participants in construction activity in order to have enough information for an analysis. In addition, the paper draws attention to the following important characteristic of construction – the critical importance of the planning stage. This is where a large number of regulatory instruments are used. There is a need to develop the nation’s corresponding regulatory framework at an advanced pace. Indeed, if construction work on a site cannot be completed and is discontinued, it may well cost as much to resume work on that site as it would to begin work on a new project. In-depth audits of the regulatory framework must begin with the planning stage. Any innovations in the regulation system must be assessed via two-way communication. The article was written on the basis of the RANEPA state assignment research program.

Child Marriage And Its Impact in Indonesia in 2021

One of the development problems that still occurs in Indonesia is the high number of child marriages. From the average figure of 9.23 percent in 2021, it still has to be lowered to achieve the target of 8.74 percent in 2024. This paper aims to look at the number of child marriages per province in Indonesia, because of the impact on child labor, not completing school, as well as policy implications. The results obtained from the literature study show that in 2021 there are 22 provinces that have child marriage rates above the national average. There are even 5 provinces that have increased from 2020. The causes of child marriage are multi-dimensional. Estimates using provincial cross-sectional data show that child marriage in Indonesia has a significant positive influence on child labor rates, on the level of not completed Junior High School education, and level of not completed Senior High School education. It takes a concerted effort from all parties so that the number of child marriages can be reduced significantly.

Broad Temperature Plateau for High Thermoelectric Properties of n-Type Bi2Te2.7Se0.3 by 3D Printing-Driven Defect Engineering

High-energy-conversion Bi2Te3-based thermoelectric generators (TEGs) are needed to ensure that the assembled material has a high value of average figure of merit (ZTave). However, the inferior ZTave of the n-type leg severely restricts the large-scale applications of Bi2Te3-based TEGs. In this study, we achieved and reported a high peak ZT (1.33) of three-dimensional (3D)-printing n-type Bi2Te2.7Se0.3. In addition, a superior ZTave of 1.23 at a temperature ranging from 300 to 500 K was achieved. The high value of ZTave was obtained by synergistically optimizing the electronic- and phonon-transport properties using the 3D-printing-driven defect engineering. The nonequilibrium solidification mechanism facilitated the multiscale defects formed during the 3D-printed process. Among the defects formed, the nanotwins triggered the energy-filtering effect, thus enhancing the Seebeck coefficient at a temperature range of 300-500 K. The effective scattering of wide-frequency phonons by multiscale defects reduced the lattice thermal conductivity close to the theoretical minimum of ∼0.35 W m-1 k-1. Given the advantages of 3D printing in freeform device shapes, we assembled and measured bionic honeycomb-shaped single-leg TEGs, exhibiting a record-high energy conversion efficiency (10.2%). This work demonstrates the great potential of defect engineering driven by selective laser melting 3D-printing technology for the rational design of advanced n-type Bi2Te2.7Se0.3 thermoelectric material.

Gender Balance on State Boards in Ireland: To the Forefront of Progress or Concealing the Status Quo?

Abstract In this article, we examine female appointments to government-owned corporations, called State Sponsored Boards (SSBs), in Ireland over a twenty-eight-year period, to analyze the extent to which gender parity has been achieved using voluntary gender targets. Using data from thirty-four SSBs, we found that overall figures relating to the achievement of gender parity on SSBs are masking the reality of female representation on these boards. We have demonstrated that the high concentration of females on particular boards is increasing the overall average gender representation figures, and as a result, a high proportion of boards are not meeting their gender targets. This research provides evidence of the importance of taking a more nuanced approach to examining gender diversity on boards as a whole.

Ultra-wideband discrete Raman amplifier optimization for single-span S-C-L-band coherent transmission systems.

We experimentally compare the performance of two key ultra-wideband discrete Raman amplifier structures, a cascaded dual-stage structure and an in-parallel dual-band structure, in fully loaded S-C-L band coherent transmission systems over 70 km of single-mode fiber. Our results show that dual-band discrete Raman amplifier with minimized backreflections can effectively avoid unstable random distributed feedback lasing, reduce the noise figure, and therefore improve the transmission performance for signals at shorter wavelengths, versus the cascaded dual-stage structure. The average noise figure for S-band signals is 6.8 dB and 7.2 dB for the dual-band structure and cascaded dual-stage structure, respectively, while the average S-band Q2 factor is similarly improved by 0.6 dB. Moreover, the cascaded dual-stage discrete Raman amplifier requires guard bands around the 1485-nm and 1508-nm pumps as the signal and pump wavelengths overlap, which results in a bandwidth loss of ∼10 nm and reduces the potential net data throughput to 28.6 Tb/s for 30-GBaud DP-16QAM signals. However, the dual-band structure can utilize the bandwidth more effectively, which leads to a higher estimated net data throughput of 31.2 Tb/s.

Vacancy-Ordered Double Perovskites Cs2BI6 (B = Pt, Pd, Te, Sn): An Emerging Class of Thermoelectric Materials.

Vacancy-ordered double perovskites (A2BX6), being one of the environmentally friendly and stable alternatives to lead halide perovskites, have garnered considerable research attention in the scientific community. However, their thermal transport has not been explored much, despite their potential applications. Here, we explore Cs2BI6 (B = Pt, Pd, Te, Sn) as potential thermoelectric materials using state-of-the-art first-principles-based methodologies, viz., density functional theory combined with many-body perturbation theory (G0W0) and spin-orbit coupling. The absence of polyhedral connectivity in vacancy-ordered perovskites gives rise to additional degrees of freedom, leading to lattice anharmonicity. The presence of anharmonic lattice dynamics leads to strong electron-phonon coupling, which is well-captured by the Fröhlich mesoscopic model. The lattice anharmonicity is further studied using ab initio molecular dynamics and the electron localization function. The maximum anharmonicity is observed in Cs2PtI6, followed by Cs2PdI6, Cs2TeI6, and Cs2SnI6. Also, the computed average thermoelectric figure of merit (zT) for Cs2PtI6, Cs2PdI6, Cs2TeI6, and Cs2SnI6 is 0.88, 0.85, 0.95, and 0.78, respectively, which reveals their promising renewable energy applications.

Reduced Thermal Conductivity in Nanostructured AgSbTe2 Thermoelectric Material, Obtained by Arc-Melting.

AgSbTe2 intermetallic compound is a promising thermoelectric material. It has also been described as necessary to obtain LAST and TAGS alloys, some of the best performing thermoelectrics of the last decades. Due to the random location of Ag and Sb atoms in the crystal structure, the electronic structure is highly influenced by the atomic ordering of these atoms and makes the accurate determination of the Ag/Sb occupancy of paramount importance. We report on the synthesis of polycrystalline AgSbTe2 by arc-melting, yielding nanostructured dense pellets. SEM images show a conspicuous layered nanostructuration, with a layer thickness of 25-30 nm. Neutron powder diffraction data show that AgSbTe2 crystalizes in the cubic Pm-3m space group, with a slight deficiency of Te, probably due to volatilization during the arc-melting process. The transport properties show some anomalies at ~600 K, which can be related to the onset temperature for atomic ordering. The average thermoelectric figure of merit remains around ~0.6 from ~550 up to ~680 K.

Державна підтримка розвитку громад в умовах фінансової децентралізації

Узагальнено повноваження органів місцевого самоврядування та ресурсне забезпечення їх реалізації. Розглянуто напрями державної фінансової підтримки розвитку громад в умовах децентралізації влади. Визначено можливості економічного розвитку громад за рахунок державної підтримки. Обґрунтовано необхідність стимулювання створення та розвитку економічно спроможних громад.

Health status of endoscopy personnel in Austria

Working in the field of endoscopy is associated with physical and psychological challenges, but we lack data as to whether it influences the health status of endoscopy personnel. The aim of the present survey was to evaluate the health status of endoscopy personnel in Austria and draw comparisons. In 2019, a standardized questionnaire of Hogrefe Publishers and a self-designed SurveyMonkey questionnaire were sent online to doctors (n=326) and nursing staff (n=234) working in the field of gastrointestinal endoscopy in Austria. The response rate was 17.9%. The data were compared with those of a standard population, a similar previous survey from 2004, and national sick leave data. Compared to a standard population of identical age and gender distribution, endoscopy personnel in Austria have more health-related complaints. Compared to doctors, nursing staff experience greater adverse effects; foremost among these are fatigue and an excessive need for sleep (p=0.001), a heavy sensation in the legs (p=0.001), hypersensitivity to warmth (p<0.001) and cold (p=0.002). Nursing staff are somewhat more frequently on sick leave than doctors. The days of sick leave were higher than those in 2004, but markedly below the average figures in Austria. Lifestyle had little influence on the respondents' symptoms. The results of the survey showed that persons working in endoscopy have slightly greater health problems than the standard population. Nursing staff are affected more severely than doctors. These data may serve as a basis for targeted preventive measures.

Atomic Level Defect Structure Engineering for Unusually High Average Thermoelectric Figure of Merit in n-Type PbSe Rivalling PbTe.

Realizing high average thermoelectric figure of merit (ZTave ) and power factor (PFave ) has been the utmost task in thermoelectrics. Here the new strategy to independently improve constituent factors in ZT is reported, giving exceptionally high ZTave and PFave in n-type PbSe. The nonstoichiometric, alloyed composition and resulting defect structures in new Pb1+ x Se0.8 Te0.2 (x = 0-0.125) system is key to this achievement. First, incorporating excess Pb unusually increases carrier mobility (µH ) and concentration (nH ) simultaneously in contrast to the general physics rule, thereby raising electrical conductivity (σ). Second, modifying charge scattering mechanism by the authors' synthesis process boosts a magnitude of Seebeck coefficient (S) above theoretical expectations. Detouring the innate inverse proportionality between nH and µH ; and σ and S enables independent control over them and change the typical trend of PF to temperature, giving remarkably high PFave ≈20 µW cm-1 K-2 from 300 to 823 K. The dual incorporation of Te and excess Pb generates unusual antisite Pb at the anionic site and displaced Pb from the ideal position, consequently suppressing lattice thermal conductivity. The best composition exhibits a ZTave of ≈1.2 from 400 to 823 K, one of the highest reported for all n-type PbQ (Q = chalcogens) materials.