bluuebunny/crossref_metadata_2025 huggingface dataset:
Peroxisome proliferator-activated receptor-α (PPARα) regulates wound healing and mitochondrial metabolism in the cornea
Authors: Liang Wentao , Huang Li , Whelchel Amy , Yuan Tian , Ma Xiang , Cheng Rui , Takahashi Yusuke , Karamichos Dimitrios , Ma Jian-Xing
Published: March 2023

Diabetes can result in impaired corneal wound healing. Mitochondrial dysfunction plays an important role in diabetic complications. However, the regulation of mitochondria function in the diabetic cornea and its impacts on wound healing remain elusive. The present study aimed to explore the molecular basis for the disturbed mitochondrial metabolism and subsequent wound healing impairment in the diabetic cornea. Seahorse analysis showed that mitochondrial oxidative phosphorylation is a major source of ATP production in human corneal epithelial cells. Live corneal biopsy punches from type 1 and type 2 diabetic mouse models showed impaired mitochondrial functions, correlating with impaired corneal wound healing, compared to nondiabetic controls. To approach the molecular basis for the impaired mitochondrial function, we found that Peroxisome Proliferator-Activated Receptor-α (PPARα) expression was downregulated in diabetic human corneas. Even without diabetes, global
PPARα
knockout mice and corneal epithelium-specific
PPARα
conditional knockout mice showed disturbed mitochondrial function and delayed wound healing in the cornea, similar to that in diabetic corneas. In contrast, fenofibrate, a PPARα agonist, ameliorated mitochondrial dysfunction and enhanced wound healing in the corneas of diabetic mice. Similarly, corneal epithelium-specific
PPARα
transgenic overexpression improved mitochondrial function and enhanced wound healing in the cornea. Furthermore, PPARα agonist ameliorated the mitochondrial dysfunction in primary human corneal epithelial cells exposed to diabetic stressors, which was impeded by siRNA knockdown of
PPARα
, suggesting a PPARα-dependent mechanism. These findings suggest that downregulation of PPARα plays an important role in the impaired mitochondrial function in the corneal epithelium and delayed corneal wound healing in diabetes.
Whale shark rhodopsin adapted to deep-sea lifestyle by a substitution associated with human disease
Authors: Yamaguchi Kazuaki , Koyanagi Mitsumasa , Sato Keiichi , Terakita Akihisa , Kuraku Shigehiro
Published: March 2023

Spectral tuning of visual pigments often facilitates adaptation to new environments, and it is intriguing to study the visual ecology of pelagic sharks with secondarily expanded habitats. The whale shark, which dives into the deep sea of nearly 2,000 meters besides near-surface filter feeding, was previously shown to possess the ‘blue-shifted’ rhodopsin (RHO), which is a signature of deep-sea adaptation. In this study, our spectroscopy of recombinant whale shark RHO mutants revealed that this blue shift is caused dominantly by an unprecedented spectral tuning site 94. In humans, the mutation at the site causes congenital stationary night blindness (CSNB) by reducing the thermal stability of RHO. Similarly, the RHO of deep-diving whale shark has reduced thermal stability, which was experimentally shown to be achieved by site 178 and 94. RHOs having the natural substitution at site 94 are also found in some Antarctic fishes, suggesting that the blue shift by the substitution at the CSNB site associated with the reduction in thermal stability might be allowed in cold-water deep-sea habitats.
Teachers’ identity and agency in L2 pragmatics
Authors: Ishihara Noriko , Mendes Porcellato Adriana , Carvalho de Almeida Prado Malila
Published: March 2023

To support multilingual speakers in drawing on their hybrid resources effectively, language teachers must embrace their own translingual practices and become critically aware of their multiple identities (Zheng, 2017). Teachers of second language (L2) pragmatics can do this by enhancing their metapragmatic awareness (McConachy, 2018). In this chapter, we uncover how two language teachers and a teacher educator collaboratively constructed this metapragmatic awareness and its application to pedagogy in and beyond a teacher development Summer Institute focused on L2 pragmatics offered remotely through a United States (U.S.) state university. Through narrative inquiry into the dialogic data collected following the Institute, we closely reflected on the Institute discussions to rediscover the translingual identities that permeated the pragmatic and pedagogical decisions the two teachers made in their translingual lives. As implications of this study, we explore ways in which language teachers can strategically deploy translingual identities as pedagogy.
Teachers’ awareness and beliefs towards corrective feedback in L2 pragmatics
Authors: Martínez-Flor Alicia
Published: March 2023

Corrective feedback (CF) has been regarded as a complex phenomenon with cognitive, social and psychological dimensions influencing its effectiveness for language development. Despite the extensive research conducted on its impact on morphosyntactic aspects of the language, CF on pragmatic aspects has received scant attention. One possible reason may be related to the potential challenges that pragmatics itself represents as it is defined by choice. Thus, it is important to examine teachers’ beliefs towards the five key pedagogical decisions that influence the provision of CF (i.e. necessity, choice of corrector, timing, types and methods of CF). With that aim in mind, this qualitative study attempts to explore in-service secondary school English as a Foreign Language (EFL) teachers’ awareness and beliefs towards CF in general and in pragmatics. To this end, a questionnaire and a follow-up interview with the participants were used to get insights on this underexplored topic.
Proficiency effects on L2 pragmatics
Authors: Roever Carsten , Shintani Natsuko , Zhu Yan , Ellis Rod
Published: March 2023

Proficiency is a widely used concept in second language (L2) pragmatics where it is commonly viewed as lexico-grammatical knowledge, and can be measured by means of standardised or researcher-designed tests, or estimated on the basis of levels in a language program. It is a common grouping variable in research studies, allowing researchers to compare the pragmatic or interactional abilities of learners at different proficiency levels, and such studies have overwhelmingly found a strong contribution of proficiency to L2 pragmatics. However, this contribution varies depending on the area of pragmatics investigated, and the degree of overlap depends strongly on the measurement instruments for both proficiency and pragmatics. We illustrate this through a study on the effect of proficiency on implicit and explicit pragmatic knowledge.
Language attitude effects on L2 pragmatics
Authors: Sánchez-Hernández Ariadna
Published: March 2023

This chapter explores the relationship between second language (L2) pragmatic competence and language attitude, an individual difference (ID) that has received scant attention in the field of Interlanguage Pragmatics. Additionally, it examines the role instruction may play in such a relationship, drawing from the idea that instruction in the foreign language context may guide students’ language attitudes and in turn enhance their L2 pragmatic skills. Seventy-three English as a Foreign Language students completed a questionnaire about attitude towards English as an International Language, and gave academic oral presentations that elicited the use of pragmatic markers. Moreover, a subset of 34 students received instruction on L2 pragmatics from an English as an International Language perspective. The results revealed an interplay among language attitude, instruction and L2 pragmatic competence which highlights the importance of focusing on students’ IDs to maximise their pragmatic learning.
A task-supported language approach to teaching L2 pragmatics
Authors: Barón Júlia
Published: March 2023

The aim of the present study is to explore the effects of a Task-Supported Language Teaching approach on second/foreign language (L2) pragmatic performance. The participants were 35 English as a Foreign Language learners with a C1 proficiency level, enrolled in a summer intensive language course. Three ‘podcast’ topic-related units were designed and incorporated into the classroom syllabus. First, students were introduced to the topic through input and metapragmatic explanations on ways of agreeing/disagreeing and showing interest that activated their schemata. Second, students were asked to work in pairs and create three podcasts. The findings show that the podcast tasks seemed to provide learners with a meaningful context so as to use the pragmatic strategies presented in the metapragmatic explanations, which were used consistently throughout the podcasts.
Switching of electromagnetic induced transparency in terahertz metasurface
Authors: Mishra Prateek , Srivastava Vibhu , Kumar Sanjeev , Rana Dhanvir Singh , Mishra Yogendra Kumar , Sunny
Published: March 2023

We demonstrate functional switching of electromagnetic induced transparency (EIT) in terahertz (THz) metasurface. We first simulated and fabricated two metasurfaces that have light difference in their unit cell design. THz time domain spectroscopy of fabricated metasurfaces shows that two metasurfaces have almost similar transmission spectra but one of them possesses EIT while the second does not. To implement functional switching of EIT, we show numerically that characteristics of both metasurfaces can be achieved by a single hybrid metasurface containing a phase change material, Ge2Sb2Te5 (GST). GST has a large contrast in THz material properties in its crystalline and amorphous phases and its phase can be rapidly interchanged by external stimuli. We incorporated GST in the unit cell and show that phase change of GST portion in the metasurface unit cell at a specific location modulates the transmission spectra working as an EIT switch. EIT in the metasurface is attributed to coupling of two opposite phases bright resonance modes supported by the unit cell. The group delay of the transmitted THz radiation indicates that THz wave slows down significantly at EIT frequency. The dynamic interplay between two different responses within a single hybrid metasurface can have applications in biosensors, THz buffers, modulators, and other functional THz communication devices.
Improving the charge carrier separation efficiency at the perovskite/carbon electrode interface in HTL-free carbon-based perovskite solar cells via physical polishing
Authors: Zhao Zeren , Wu Yulin , Wu Shan , Li Chao , Ma Fangyuan , Ma Mengmeng , Tang Xuan , Wang Jinyao , Zhou Liya , He Xipu , Wang Zhijie , Liu Kong , Yue Shizhong , Qu Shengchun
Published: March 2023

Carbon-based perovskite solar cells (C-PSCs) are favored by researchers for their low cost and support for large-scale production. However, the particles precipitated on the surface of the perovskite (PVK) film can affect the fabrication and operation of C-PSC, such as disrupting the coating of C electrode film and producing defects that can aggravate the carrier recombination. Herein a reliable and efficient C-PSC is prepared by applying a physical polishing strategy. The compact interface contact and the larger Fermi level difference at the carbon-PVK (C/PVK) interface are achieved, resulting in a 21.4% increase in power conversion efficiency compared to that without polishing. A hole-transport-layer-free C-PSC with an efficiency of 12.2% is achieved, resulting from the reduction of PVK surface roughness and defects that cause non-radiative recombination. It is revealed that the physical polishing can reduce the root mean square roughness from 15.9 nm to 1.2 nm, facilitating the screen printing of the C electrode. The carrier lifetime of the PVK film also increases from 39.9 ns to 73.3 ns, which improves the photocurrent of the solar cell. We believe that the improved C/PVK interface contact will provide a solid foundation for the future large-scale commercial production of PSCs.
Gas flow calibration standard device for working site
Authors: Niu LiNa , Yang GuangLei , Yang ShiQi , Zang XianLe , Song YaJing
Published: March 2023

A portable on-site gas flow standard device based on the standard meter method is designed to ensure metering accuracy in the natural gas trade. The standard device is optimized using computation fluid dynamics simulation technology. The acquisition of high and low frequency pulse signals, video photoelectric signals, and manual trigger signals is realized. Non-fixed-point measurement is realized by corrected linear interpolation of fixed-point and least-squares construction of the instrument coefficient correlation. The flow rate range of the device is (0.65–650) m3 h−1 and the expanded uncertainty is 0.33% (k= 2). The device is compact, portable, and can be carried on a vehicle for on-site application. The device is compared with the bell-type gas flow standard device and the sonic nozzle gas flow standard device of Hebei Metrology Supervision and Inspection Institute. The experimental results show that the E
n value of the device is 0.67, and the measurement repeatability is better than 0.12 %.
Deep learning-based methods in structural reliability analysis: a review
Authors: Afshari Sajad Saraygord , Zhao Chuan , Zhuang Xinchen , Liang Xihui
Published: March 2023

One of the most significant and growing research fields in mechanical and civil engineering is structural reliability analysis (SRA). A reliable and precise SRA usually has to deal with complicated and numerically expensive problems. Artificial intelligence-based, and specifically, Deep learning-based (DL) methods, have been applied to the SRA problems to reduce the computational cost and to improve the accuracy of reliability estimation as well. This article reviews the recent advances in using DL models in SRA problems. The review includes the most common categories of DL-based methods used in SRA. More specifically, the application of supervised methods, unsupervised methods, and hybrid DL methods in SRA are explained. In this paper, the supervised methods for SRA are categorized as multi-layer perceptron, convolutional neural networks, recurrent neural networks, long short-term memory, Bidirectional LSTM and gated recurrent units. For the unsupervised methods, we have investigated methods such as generative adversarial network, autoencoders, self-organizing map, restricted Boltzmann machine, and deep belief network. We have made a comprehensive survey of these methods in SRA. Aiming towards an efficient SRA, DL-based methods applied for approximating the limit state function with first/second order reliability methods, Monte Carlo simulation (MCS), or MCS with importance sampling. Accordingly, the current paper focuses on the structure of different DL-based models and the applications of each DL method in various SRA problems. This survey helps researchers in mechanical and civil engineering, especially those who are engaged with structural and reliability analysis or dealing with quality assurance problems.
Growth of quasi-1 dimensional (Bi1−x
Sb
x
)2S3 nanowires on fluorine-doped tin oxide glass substrate by vapor transport
Authors: Oh Seung Hwan , Izziyah Asna N , Kim Yong
Published: March 2023

(Bi1−x
Sb
x
)2S3 solid solution nanowires (

0
≤
x
≤
0.73

) are grown on fluorine-doped tin oxide (FTO) glass via physical vapor transport. The compositions were controlled by varying the Sb2S3 source temperature (300 °C–453 °C) by changing the upstream locations of the Sb2S3 source in the furnace while keeping the Bi2S3 source at the center of the furnace (497 °C). Defect-free nanowires with phase-pure orthorhombic and quasi-1 dimensional crystal structures were grown under a modified vapor–solid mechanism affected by FTO at initial growth stage. The aspect ratios of the nanowires reached the minimum at composition

x
∼
0.6
.

As the Sb2S3 source approached the Bi2S3 source, x increased owing to the increase in the Sb2S3 source temperature. x/(1-x), which is proportional to the evaporation flux of the Sb2S3 source, could be well-fitted with a thermally activated equation with an apparent activation energy (

105

kJ

mol

-
1

). However, at the distance between the Sb2S3 and Bi2S3 sources, with the Sb2S3 source at temperatures higher than 410 °C, the compositions reduced despite the increased Sb2S3 evaporation flux. Such retrograde behavior was confirmed by high-resolution transmission electron microscopy, x-ray diffraction, and micro-Raman studies. This retrograde behavior is ascribed to the loss due to the reaction of gaseous Sb species with the Bi2S3 source.
JAAL-Net: a joint attention and adversarial learning network for skin lesion segmentation
Authors: Xiong Siyu , Pan Lili , Lei Qianhui , Ma Junyong , Shao Weizhi , Beckman Eric
Published: March 2023

Objective. Skin lesion segmentation plays an important role in the diagnosis and treatment of melanoma. Existing skin lesion segmentation methods have trouble distinguishing hairs, air bubbles, and blood vessels around lesions, which affects the segmentation performance. Approach. To clarify the lesion boundary and raise the accuracy of skin lesion segmentation, a joint attention and adversarial learning network (JAAL-Net) is proposed that consists of a generator and a discriminator. In the JAAL-Net, the generator is a local fusion network (LF-Net) utilizing the encoder-decoder structure. The encoder contains a convolutional block attention module to increase the weight of lesion information. The decoder involves a contour attention to obtain edge information and locate the lesion. To aid the LF-Net generate higher confidence predictions, a discriminant dual attention network is constructed with channel attention and position attention. Main results. The JAAL-Net is evaluated on three datasets ISBI2016, ISBI2017 and ISIC2018. The intersection over union of the JAAL-Net on the three datasets are 90.27%, 89.56% and 80.76%, respectively. Experimental results show that the JAAL-Net obtains rich lesion and boundary information, enhances the confidence of the predictions, and improves the accuracy of skin lesion segmentation. Significance. The proposed approach effectively improves the performance of the model for skin lesion segmentation, which can assist physicians in accurate diagnosis well.
18F-PSMA-1007 salivary gland dosimetry: comparison between different methods for dose calculation and assessment of inter- and intra-patient variability
Authors: Pistone Daniele , Gnesin Silvano , Auditore Lucrezia , Italiano Antonio , Cascini Giuseppe Lucio , Amato Ernesto , Cicone Francesco
Published: March 2023

Objective. Simplified calculation approaches and geometries are usually adopted for salivary glands (SGs) dosimetry. Our aims were (i) to compare different dosimetry methods to calculate SGs absorbed doses (ADs) following [18F]-PSMA-1007 injection, and (ii) to assess the AD variation across patients and single SG components. Approach. Five patients with prostate cancer underwent sequential positron-emission tomography/computed tomography (PET/CT) acquisitions of the head and neck, 0.5, 2 and 4 h after [18F]-PSMA-1007 injection. Parotid and submandibular glands were segmented on CT to derive SGs volumes and masses, while PET images were used to derive Time-Integrated Activity Coefficients. Average ADs to single SG components or total SG (tSG) were calculated with the following methods: (i) direct Monte Carlo simulation with GATE/GEANT4 considering radioactivity in the entire PET/CT field-of-view (MC) or in the SGs only (MCsgo); (ii) spherical model (SM) of OLINDA/EXM 2.1, adopting either patient-specific or standard ICRP89 organ masses (SMstd); (iii) ellipsoidal model (EM); (iv) MIRD approach with organ S-factors from OLINDA/EXM 2.1 and OpenDose collaboration, with or without contribution from cross irradiation originating outside the SGs. The maximum percent AD difference across SG components (δ
max) and across patients (Δmax) were calculated. Main results. Compared to MC, ADs to single SG components were significantly underestimated by all methods (average relative differences ranging between −11.9% and −30.5%). δ
max values were never below 25%. The highest δ
max (=702%) was obtained with SMstd. Concerning tSG, results within 10% of the MC were obtained only if cross-irradiation from the remainder of the body or from the remainder of the head was accounted for. The Δmax ranged between 58% and 78% across patients. Significance. Simple geometrical models for SG dosimetry considerably underestimated ADs compared to MC, particularly if neglecting cross-irradiation from neighboring regions. Specific masses of single SG components should always be considered given their large intra- and inter-patient variability.
PET AIF estimation when available ROI data is impacted by dispersive and/or background effects
Authors: O’Sullivan Finbarr
Published: March 2023

Objective. Blood pool region of interest (ROI) data extracted from the field of view of a PET scanner can be impacted by both dispersive and background effects. This circumstance compromises the ability to correctly extract the arterial input function (AIF) signal. The paper explores a novel approach to addressing this difficulty. Approach. The method involves representing the AIF in terms of the whole-body impulse response (IR) to the injection profile. Analysis of a collection/population of directly sampled arterial data sets allows the statistical behaviour of the tracer’s impulse response to be evaluated. It is proposed that this information be used to develop a penalty term for construction of a data-adaptive method of regularisation estimator of the AIF when dispersive and/or background effects maybe impacting the blood pool ROI data. Main results. Computational efficiency of the approach derives from the linearity of the impulse response representation of the AIF and the ability to substantially rely on quadratic programming techniques for numerical implementation. Data from eight different tracers, used in PET cancer imaging studies, are considered. Sample image-based AIF extractions for brain studies with: 18F-labeled fluoro-deoxyglucose and fluoro-thymidine (FLT), 11C-labeled carbon dioxide (CO2) and 15O-labeled water (H2O) are presented. Results are compared to the true AIF based on direct arterial sampling. Formal numerical simulations are used to evaluate the performance of the AIF extraction method when the ROI data has varying amounts of contamination, in comparison to a direct approach that ignores such effects. It is found that even with quite small amounts of contamination, the mean squared error of the regularised AIF is significantly better than the error associated with direct use of the ROI data. Significance. The proposed IR-based AIF extraction scheme offers a practical methodological approach for situations where the available image ROI data may be contaminated by background and/or dispersion effects.
Statistical genetics in and out of quasi-linkage equilibrium
Authors: Dichio Vito , Zeng Hong-Li , Aurell Erik
Published: March 2023

This review is about statistical genetics, an interdisciplinary topic between statistical physics and population biology. The focus is on the phase of quasi-linkage equilibrium (QLE). Our goals here are to clarify under which conditions the QLE phase can be expected to hold in population biology and how the stability of the QLE phase is lost. The QLE state, which has many similarities to a thermal equilibrium state in statistical mechanics, was discovered by M Kimura for a two-locus two-allele model, and was extended and generalized to the global genome scale by Neher & Shraiman (2011). What we will refer to as the Kimura–Neher–Shraiman theory describes a population evolving due to the mutations, recombination, natural selection and possibly genetic drift. A QLE phase exists at sufficiently high recombination rate (r) and/or mutation rates µ with respect to selection strength. We show how in QLE it is possible to infer the epistatic parameters of the fitness function from the knowledge of the (dynamical) distribution of genotypes in a population. We further consider the breakdown of the QLE regime for high enough selection strength. We review recent results for the selection-mutation and selection-recombination dynamics. Finally, we identify and characterize a new phase which we call the non-random coexistence where variability persists in the population without either fixating or disappearing.
Two-dimensional CrP2 with high specific capacity and fast charge rate for lithium-ion battery
Authors: Wang Xiaoyun , Jing Tao , Liang Dongmei
Published: March 2023

The electrode material is regarded as one of the key factors that determine the performance of lithium-ion batteries (LIBs). However, it is still a challenge to search for an anode material with large capacity, low diffusion barrier, and good stability. In the present work, two new CrP2 monolayers (Pmmn-CrP2 and Pmma-CrP2) are predicted by means of first principles swarm structure search. Our study shows that both the two CrP2 monolayers have high dynamical and thermal stability, as well as excellent electron conductivity. Additionally, Pmmn-CrP2 exhibits a remarkably high storage capacity of 705 mA⋅h⋅g−1 for Li, meanwhile the diffusion energy barrier of Li on the surface of this monolayer is 0.21 eV, ensuring it as a high-performance anode material for LIBs. We hope that our study will inspire researchers to search for new-type two-dimensional (2D) transition metal phosphides for the electrode materials of LIBs.
Decoding study-independent mind-wandering from EEG using convolutional neural networks
Authors: Jin Christina Yi , Borst Jelmer P , van Vugt Marieke K
Published: March 2023

Objective. Mind-wandering is a mental phenomenon where the internal thought process disengages from the external environment periodically. In the current study, we trained EEG classifiers using convolutional neural networks (CNNs) to track mind-wandering across studies. Approach. We transformed the input from raw EEG to band-frequency information (power), single-trial ERP (stERP) patterns, and connectivity matrices between channels (based on inter-site phase clustering). We trained CNN models for each input type from each EEG channel as the input model for the meta-learner. To verify the generalizability, we used leave-N-participant-out cross-validations (N = 6) and tested the meta-learner on the data from an independent study for across-study predictions. Main results. The current results show limited generalizability across participants and tasks. Nevertheless, our meta-learner trained with the stERPs performed the best among the state-of-the-art neural networks. The mapping of each input model to the output of the meta-learner indicates the importance of each EEG channel. Significance. Our study makes the first attempt to train study-independent mind-wandering classifiers. The results indicate that this remains challenging. The stacking neural network design we used allows an easy inspection of channel importance and feature maps.
The late to early time behaviour of an expanding plasma: hydrodynamisation from exponential asymptotics
Authors: Aniceto Inês , Hasenbichler Daniel , Olde Daalhuis Adri
Published: March 2023

We use exponential asymptotics to match the late time temperature evolution of an expanding conformally invariant fluid to its early time behaviour. We show that the rich divergent transseries asymptotics at late times can be used to interpolate between the two regimes with exponential accuracy using the well-established methods of hyperasymptotics, Borel resummation and transasymptotics. This approach is generic and can be applied to any interpolation problem involving a local asymptotic transseries expansion as well as knowledge of the solution in a second region away from the expansion point. Moreover, we present global analytical properties of the solutions such as analytic approximations to the locations of the square-root branch points, exemplifying how the summed transseries contains within itself information about the observable in regions with different asymptotics.
Connection problem of the first Painlevé transcendents with large initial data
Authors: Long Wen-Gao , Li Yu-Tian
Published: March 2023

In previous work, Bender and Komijani (2015 J. Phys. A: Math. Theor.
48 475202) studied the first Painlevé (PI) equation and showed that the sequence of initial conditions giving rise to separatrix solutions could be asymptotically determined using a

-symmetric Hamiltonian. In the present work, we consider the initial value problem of the PI equation in a more general setting. We show that the initial conditions

(
y
(
0
)
,

y

′

(
0
)
)
=
(
a
,
b
)

located on a sequence of curves

Γ
n

,

n
=
1
,
2
,
…

, will give rise to separatrix solutions. These curves separate the singular and the oscillating solutions of PI. The limiting form equation

b
2

/

4
−

a
3

=

f
n

∼
A

n

6

/

5

for the curves

Γ

n

as

n
→
∞

is derived, where A is a positive constant. The discrete set

{

f
n

}

could be regarded as the nonlinear eigenvalues. Our analytical asymptotic formula of

Γ
n

matches the numerical results remarkably well, even for small n. The main tool is the method of uniform asymptotics introduced by Bassom et al (1998 Arch. Rational Mech. Anal.
143 241–71) in the studies of the second Painlevé (PII) equation.
Study on an air conditioning system with the use of natural cooling
Authors: Izzatillaev J , Axmatova S , Usmonov N , Diyorov R
Published: March 2023

Issues of microclimate mitigation in Uzbekistan during the summer period require urgent resolution. It should be noted that currently there are very few researches, as well as practical recommendations related to the formation of a favorable microclimatic environment in cities with a hot climate. The simplest and most economical way of cooling, in dry and hot climates, is the evaporative cooling of a dry air stream. One of the possible ways to increase the efficiency of the system is the use of night evaporative cooling of water, followed by its accumulation for daytime cooling in heat-insulated batteries. The conducted experiments testify that rather simple and cheap natural sources of cold can be used along with machine cold sources for air conditioning of residential buildings in Uzbekistan.
Change in the structure of the focal spot at the focus of a large solar furnace from the visible angle of the Sun
Authors: Sabirov Y , Makhmudov S , Abdurakhmanov A , Akhmadov Sh , Kholov Sh
Published: March 2023

In this work, for the first time, the coincidence of the proposed theoretical foundations of the methodology for calculating the dimension and energy characteristics of an optical image is shown, in contrast to the previously known to substantiate the separate consideration of the apparent angular size of the Sun 2γ from the accuracy parameters of manufacturing the SCS BLB (γ+Δα). On the example of a comparative assessment of operational measurements with the calculated ones during the past eclipses, where changes in the value of 2γ took place while the value of Δα was constant. These comparative estimates of theoretical and experimental results were carried out during partial solar eclipses that took place on August 1, 2008 and December 26, 2019.
Improving the gravity-vortex micro-hydroelectric power station efficiency by ensuring an acceptable value of the water inlet canal’s twist angle
Authors: Mamadjanov A B , Zakhidov R A , Rakhmatov A , Sharipov F
Published: March 2023

Micro-water energy is a promising alternative energy source that produces electricity in remote areas, separated from the main electricity grid. In this research work, the method of increasing the efficiency of gravity-vortex micro-hydroelectric power station operating in low-pressure water flows through the twist angle of the inlet channel of the basin is presented. Gravity-vortex micro-hydroelectric power station is a new modern green technology as an alternative or renewable energy source. The advantage of this method of electricity production is that it is possible to produce electricity at a low pressure, i.e. starting from a pressure of 0.7 meters. In order to increase the initial speed of the water entering the cylindrical basin, the flow fields of the water flow inside the basin in the range of 0-90 degrees of the inlet channel twist angle were numerically simulated using the ANSYS Fluent software. As a result of the study, the parameters of the influence of the flow velocity vector on the flow field were studied.
Efficiency and environmental indicators of diesel engine operation when using water injection
Authors: Musabekov Z , Ergashev B , Daminov O , Khushnaev O , Kurbanov A , Kukharonok G
Published: March 2023

The indicator diagram of the D-240 diesel engine was built taking into account the data obtained from the calculation of the working process. The construction of the indicator chart was carried out analytically using the Microsoft Excel application package. As a result of mathematical modeling, it was found that at the nominal operating mode of the D-240 diesel engine, the introduction of 30% of water from the cycle supply of diesel fuel into the fuel-air mixture makes it possible to increase the effective power from 55.15 kW to 65.84 kW. The reduction in the specific effective consumption of diesel fuel is 45 gr/(kW/h). The thermal efficiency of the engine under study is 35.57%.
Study on the process automatization of wetting (moistening) the seeds using a step motor
Authors: Denmukhammadiev A , Pardaev A , Kucharov F , Isaev A
Published: March 2023

Researcher Urishev was the first to deal with the issues of mechanization of the process of moistening cotton seeds in the Republic of Uzbekistan. He also developed many devices and mechanisms and proposed methods for conducting experiments on moistening pubescent cotton seeds. However, his works did not address the issues of automation of laboratory facilities. And also Urishev used chemicals for seed treatment, which is harmful to humans and the environment. The creation of an environmentally friendly technology for presowing disinfection of cotton seeds is an urgent task for cotton growing. Research in this field of science has led to the use of electrical energy as the most harmless and cheap means. Along with researchers studying electrical technology in the Republic of Uzbekistan, under the guidance of Professor Mukhammadiev, research work has been carried out since 1985: to develop a non-chemical technology for growing cotton using a spark discharge current, an alternating electric current of industrial frequency. In this article, the possibilities of automating the process of lifting and lowering a laboratory test mechanism for studying the friction of dry and moist cotton seeds proposed by Urishev with the help of a stepper motor were studied in order to automate the process of laboratory experiments. We also obtained equations for finding the resulting force.
Analysis of the methods of diagnosing asynchronous motors according to vibration indicators
Authors: Ibragimov M , Akbarov D , Fayziyev M , Beytullaeva R , Nimatov K , Safarov Kh S
Published: March 2023

Currently, AC motors are in great demand among most modern manufacturing enterprises. Professional experience shows that they use 80% of all electricity generated in the country, so the stability of their work plays an important role in agriculture and industry. Nowadays, vibration diagnostics is one of the effective tools for solving a wide range of problems of detecting defects in electrical machines, preventing parts from failing, extending their service life and increasing their overhaul periods of operation. Preservation of electrical safety, reliability and durability of the operation of electromechanical equipment of electric drives based on asynchronous motors in the production processes of enterprises in the agricultural industry remains an urgent task of electrical systems.
Comparative analysis of noise levels available on simple and rubber granule asphalt-concrete coating roads
Authors: Ismayilov K , Karimova K , Azimov A , Raxmatov U
Published: March 2023

In this article, a scientific study was conducted and studied on the effect of road surface on traffic noise level. The experiment was conducted on two different paved roads and the noise levels were based on international standards. The results of research conducted on asphalt-concrete paved roads with the addition of rubber granules found that the noise levels on high-quality bitumen-paved asphalt concrete paved roads differ from the noise sources. By giving several recommendations for the organization of noise protection have been developed.
Experimental study on traditional timber-concrete hybrid house with different types of roofs using shake table
Authors: Mahmoud M A S A , Lau T L
Published: March 2023

Buildings with different roofing systems possess different seismic performance during earthquake. Most of the traditional buildings are susceptible to earthquake disaster due to no seismic loading is considered in the design. In addition, irregular buildings have been proven to perform badly during earthquake events. Due to lack of investigations on asymmetrical timber-concrete hybrid building under earthquake loading, a ¼ of this type of building model was tested seismically using a unidirectional shake table. Four structural models with frequencies 3.85 Hz, 3.33 Hz, 2.70 Hz and 2.50 Hz varied using diagonal wooden braces and different roof materials namely heavy metal roof and clay roof tile. The models were subjected to El Centro ground motion excitations scaled to 0.08 g, 0.16 g, 0.24 g and 0.32 g PGA resembling 25%, 50%, 75% and 100% of the actual ground motion strength, respectively. Nine accelerometers and seven LVDTs were used to measure the seismic response of the models during shake table test for acceleration and displacement, respectively. Heavier roof material shows a different trend in the amplitudes across the maximum displacement time history, but a clear decrease in acceleration response for the roof level as compared with lighter roof material.
Methods for improving efficiency in cattle farms via innovations in Uzbekistan
Authors: Mamadiyorov D , Mardiev N , Siddikov Z , Toshboev A , Narinbaeva G
Published: March 2023

Our article discusses ways to increase efficiency through the application of innovations in farms specializing in animal husbandry. Livestock is one of the leading sectors of agriculture in Uzbekistan. Meat, dairy and egg products of the population provide the industry with leather, wool and other raw materials. In today’s market economy, one of the most important tasks is to provide the population of Uzbekistan with high quality, environmentally friendly and affordable livestock products. There are many branches of the livestock industry, such as cattle breeding, sheep breeding, poultry farming, horse breeding, fishing, beekeeping. Therefore, the main tasks of the development of these industries are to build a strong fodder base, to provide livestock with a variety of cervitamines, protein-rich, nutritious feeds throughout the year, to properly organize breeding and selection work, based on best practices and scientific achievements such as efficient use, cost-saving new equipment, introduction of innovative efficient technologies, mechanization of production processes, increasing the level of automation, widespread introduction of modern advanced technologies in practice and specialization of farms in formed production and other factors.
Properties and indicators of fertility of bogarian soils formed in different soil-forming rocks
Authors: Raimbaeva G Sh , Mirkhaidarova G S
Published: March 2023

Soil-forming rocks of the tertiary period are widespread, most of which have a clay composition, are highly compacted and cause more extreme regimes, which cannot but affect biological conditions and, in total, soil formation and fertility. In this research, all experiment were carried out in the study area in Chirchik-Keles in Tashkent region. The results showed that depending on the parent rock, the degree of erosion, soil composition, and the density of the solid phase of soils varied from 2.60 up to 2.72 g/cm3 and is 2.59-2.61 g/cm3 in the upper humus horizons, and 2.67-2.72 g/cm3 in the lower ones. Moreover, for soils on Tertiary deposits, the values were somewhat higher, which can be explained by the peculiarities of the mineralogical composition.
Study on the quality indicators of apple varieties grown at low level under-grafted M-9
Authors: Boboeva Khilola
Published: March 2023

This work used the generally accepted modern methods and programs for the variety study of fruit plants developed at the Research Institute of Horticulture, Viticulture and Winemaking named after Academician Makhmud Mirzaev. The aim of the study was to select the source material of the apple fruit quality introduced in Tashkent region and 35 local varieties of apples, which is valuable for the breeding, and the sources of the target traits based on the analysis of long-term data on the assessment of the biochemical composition of promising varieties of different apples. According to the results, Williams Pride, “Isroil”, Kuban crimson, Esaul’s memory, and Mutsu varieties differed from other varieties with high quality.
Study on the clathrates and polymorphes of plant polyphenols
Authors: Honkeldieva M , Bukhorov K , Sayfiyeva M , Choriyeva G
Published: March 2023

Gossypol is secondary metabolite that play diverse role in plant adaptation to environment. Obtained from cottonseeds gossypol has valuable biological properties and forms an abundant number of clathrates with a large variety of compounds. One of the primary reasons why gossypol can form clathrates is its ability to organize extensive hydrogen bonding networks due to its hydroxyl and aldehyde functional groups. Less hundred clathrates as single crystals have been obtained and their crystallographic parameters have been determined. Solutions were prepared by adding 0.5 g of gossypol and 6.0 ml (6.3 g) of acetic acid, 4.0 ml (3 g) of acetone, 5.0 ml (4.5 g) of ethyl acetate, 2 ml (2.0 g) of 1,4-dioxane, 9.0 ml (13.4 g) of chloroform, 11.0 ml (9.6 g) of benzene to six small glasses vials at room temperature. The structures of 30 inclusion complexes have been solved by diffraction methods. This natural polyphenol forms stable clathrates with acetic acid, acetone, ethyl acetate, 1,4-dioxane, chloroform and benzene. This work describes investigation of gossypol clathrates by single-crystal diffraction and thermal analysis.
Creation of improved UXK equipment for cleaning cotton from large impurities
Authors: Usmankulov A , Salomov A , Abbazov I , Egamberdiev F
Published: March 2023

This article establishes a number of requirements for cotton fiber processing enterprises to improve production efficiency and rational use of resources and maintain high rates of natural quality of cotton fiber during processing. In addition, as a result of the research, it was found that changing the impact pressure of the scraper brush, creating a new shape of the scraper device, changing the relative position of the grate and the scraper brush, placing an additional scraper device after the scraper brush, so as not to be part of the dirty mixture that separates the piece of cotton, were found some positive results. The proposed design of the cotton cleaning section of the UXK purifier, due to the above features, makes it possible to increase the cleaning effect compared to the existing purifier, since in the proposed version, the process of cleaning cotton from large impurities is carried out twice in each section of the USC, which cleans cotton from large impurities. The proposed technical solution was taken as a basis and a plan was developed for preparing its structural diagrams and working drawings, manufacturing a laboratory stand for the cleaning section, conducting laboratory experiments with it, substantiating the main parameters of the working bodies according to the proposed scheme, and introducing the proposal into production.
Evaluation of qualitative parameters of fiber in cotton hybrids grown in various regions of Uzbekistan
Authors: Juraev S , Jumashev M , Khudarganov K , Nazarov Kh
Published: March 2023

The hybrids of medium-fiber cotton were assessed in terms of fiber quality in the Tashkent, Fergana and Kashkadarya regions of the Republic of Uzbekistan. 4 hybrid combinations of different genetic origin were tested. The analysis of the influence of the genotype and the environment on the manifestation of the qualitative parameters of the fiber (length, specific breaking load, micronaire) was carried out. High values were found in hybrids involving the wild speciesG. trilobumSkovsted and the ruderal formG. HarknessiiBrand. as well as varieties Bukhara-6. As a result of three years of experiments, it was found that the genotype and unaccounted factors influence the variability of the fiber length to a greater extent. The genotype rather than the environment significantly affects the specific breaking load of the fiber. The variability of the micronaire fiber is more dependent on environmental conditions.
Variability of main value-economic characteristics of F2-F4 hybrids of cotton in different soil-climate regions of Uzbekistan
Authors: Juraev S , Makhammatova M , Jumashev M , Ashurov M
Published: March 2023

One of the important problems in cotton breeding is the creation of high-yielding, fast-maturing varieties with high fiber yield and quality and their wide use in production. Due to the increase in the number of people on earth and the reduction of irrigated arable land, it is important to get a high quality harvest suitable for different soil and climate regions without expanding the arable land. This research intended to study the variability of the observed characters in the phenotype of the cotton plant during the selection of four F2-F4 hybrid combinations in the conditions of Tashkent, Fergana and Kashkadarya regions. During the research experiments, classical genetic-selection methods of cotton, hybridological analysis methods, comparative morphology, phenological observations and genetic-statistical analysis methods were used. The results showed that the average indicators of this sign were approximately the same in Fergana and Kashkadarya regions, accounted for 116.5 and 117 days, which was 12 days shorter than the growth period of this hybrid in Tashkent region. Similarly, insignificant changes of the above combinations were also observed in the experiments of 2019 and 2020. It was found that in F2 [(F8 L-247 x S-484) x F15 L-248], the fiber length variation was not significantly affected by the environment, the variation ranged from 0.04 inches to 0.07 inches.