bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy Deficit and Factors Associated with Energy Balance during a Combat Deployment in U.S. Army Special Operation Forces Soldiers
Authors: Tryon Evan G. , Barringer Nicholas D. , Lieberman Harris R. , Conkright William R.
Published: September 2024

The purpose of this study was to determine the difference between estimated energy expenditure (EE) and self-reported dietary intake (EI), and factors associated with energy balance in deployed U.S. Army Special Operations Forces (SOF) Soldiers. Methods: Forty-six SOF Soldiers (age: 30.1 ± 3.5 yrs, body mass index: 27.7 ± 4.1 kg/m2) completed surveys on demographic data, mission activity characteristics, gastrointestinal issues, ration consumption, resilience, mood state, and dietary intake using a 127-question food frequency questionnaire at the end of a six-month deployment. EE was estimated using a SOF-specific prediction equation with a physical activity factor of 2.1. A paired t-test compared reported energy intake (EI) with estimated energy expenditure (EE). Pearson correlations identified significant variables associated with energy balance, which were then incorporated into a multiple linear regression model. The regression analysis included Profile of Mood States (POMS) anger and POMS depression as predictor variables to determine their influence on energy balance. Results: Reported mean EI was 2512 ± 1059 kcal·d−1, while estimated mean EE was 5272 ± 525 kcal·d−1. The mean energy imbalance was −2854 kcal/d (95% CI: −2655 to −3055, p < 0.001), with all participants in negative energy balance (range: −492 to −3813 kcal/d). POMS depression (r = 0.517, p < 0.01) and POMS anger (r = 0.363, p = 0.020) were associated with energy balance. The regression model was significant (R2 = 0.23, F (2, 38) = 7.02, p < 0.01), with POMS depression significantly predicting energy balance (β = 50.76, p = 0.011). Conclusions: Deployed SOF Soldiers reported high EE and limited EI, which may negatively impact performance. Higher POMS depression scores were associated with lower energy deficits. Future studies should investigate the relationship between mood and energy balance, using direct measures of EI and EE.
Lactoferrin: A Promising Therapeutic Molecule against Human Papillomavirus
Authors: Kaplan Merve , Baktıroğlu Merve , Kalkan Arda Erkan , Canbolat Ahmet Alperen , Lombardo Mauro , Raposo António , de Brito Alves José Luiz , Witkowska Anna Maria , Karav Sercan
Published: September 2024

Lactoferrin is a multifunctional glycoprotein naturally found in mammalian secretions, predominantly in colostrum and milk. As a key component of dairy foods, lactoferrin enhances viral protection and boosts human health, owing to its fundamental properties including antiviral, anti-inflammatory, and immune-modulatory effects. Importantly, the antiviral effect of lactoferrin has been shown against a range of viruses causing serious infections and threatening human health. One of the viruses that lactoferrin exerts significant antiviral effects on is the human papillomavirus (HPV), which is the most prevalent transmitted infection affecting a myriad of people around the world. Lactoferrin has a high potential to inhibit HPV via different mechanisms, including direct binding to viral envelope proteins or their cell receptors, thereby hindering viral entry and immune stimulation by triggering the release of some immune-related molecules through the body, such as lymphocytes. Along with HPV, lactoferrin also can inhibit a range of viruses including coronaviruses and hepatitis viruses in the same manner. Here, we overview the current knowledge of lactoferrin and its effects on HPV and other viral infections.
Comparative Efficacy of Low-Carbohydrate and Ketogenic Diets on Diabetic Retinopathy and Oxidative Stress in High-Fat Diet-Induced Diabetic Rats
Authors: Jawharji Monya T. , Alshammari Ghedeir M. , Binobead Manal Abdulaziz , Albanyan Nouf Mohammed , Al-Harbi Laila Naif , Yahya Mohammed Abdo
Published: September 2024

This study examined the effect of a low-carbohydrate diet (LCD) and a low-carbohydrate ketogenic diet (LCKD) on diabetic retinopathy in high-fat diet-induced diabetes mellitus in rats and studied the mechanisms of action. Rats were divided into four groups: the Control group, which was fed a normal diet for 16 weeks; the HFD group, which was fed a high-fat diet (HFD) for the first 8 weeks and then switched to a normal diet for 8 weeks; the HFD+LCD group, fed a HFD for 8 weeks followed by an LCD for 8 weeks, and the HFD+LCKD group, which was fed a HFD for 8 weeks followed by an LCKD for 8 more weeks. Both the LCD and the LCKD effectively reduced the final body and total fat weights and decreased fasting serum levels of glucose, insulin, hemoglobin A1 (HbA1C), triglycerides, cholesterol, and LDL-c. They also reduced the levels of malondialdehyde (MDA), tumor necrosis factor-α, vascular endothelial factor, caspapse-3, and bax. In the HFD rats, we found increased serum levels of β-Hydroxybutyrate and upregulated expression of Bcl2, glutathione, superoxide dismutase, and hemeoxygenase-1. Moreover, the LCD and LCKD significantly reduced mRNA levels of Kelch-like ECH-associated protein 1 (Keap1) and enhanced mRNA and nuclear concentrations of nuclear factor erythroid factor 2 (Nrf2). All these effects were associated with improved layers of the retina in the HFD − LCD and HFD + LCKD rats but not in HFD animals. The impact of the LCKD was always more profound on all measured parameters and on improving the structure of the retina compared to the LCD. In conclusion, the LCKD is superior to the LCD in preventing diabetic retinopathy in HFD-fed rats. Mechanistically, our results suggest that the hypoglycemic and hypolipidemic conditions and the Nrf2-dependent antioxidant and anti-inflammatory effects may be involved in the preventative effects of the LCD and LCKD.
Postbiotics: Mapping the Trend
Authors: Stelmach Veroniki , Stavrou George , Theodorou Ioannis , Semertzidou Eleni , Tzikos Georgios , Menni Alexandra-Eleftheria , Shrewsbury Anne , Ioannidis Aris , Kotzampassi Katerina
Published: September 2024

Background: Since the consensus of ISAPP on the definition of the term “postbiotic” there has been an enthusiasm for publications in review form—their number being disproportionate to the primary research. The aim of this bibliometry is to analyze the bibliometric trends of this newfound interest in the field. Methods: Search of the PubMed database for review articles on postbiotics, published between November 2021 and June 2024. Results: Analysis was performed on 92 review articles, the number corresponding to 2.9 reviews per month. China, Poland, Italy, Iran and India had the maximum productivity among the 32 countries involved; 21 articles were published in 13 journals with the highest impact factor, while 45 were in 16 journals with an IF between 4.0 and 4.9. The authors were mainly affiliated to universities with specialization in both basic research and technology, as well as food science. The top five publications regarding the citations received, published in Foods (2), EBioMedicine, Biomolecules, and Front. Nutr., have collected between 138 and 109 citations. Conclusions: The ever-growing number of reviews regarding postbiotics is perhaps disproportionate to the actual original research in the field. Further clinical trials would extend and deepen the subject and facilitate the drowning of more robust conclusions in relation to their effects.
Black Hole’s Spin-Dependence of γ-Ray and Neutrino Emissions from MAXI J1820+070, XTE J1550-564, and XTE J1859+226
Authors: Rarras Dimitrios , Kosmas Odysseas , Papavasileiou Theodora , Kosmas Theocharis
Published: September 2024

A black hole’s spin effects on the jet emissions of high-energy neutrinos and γ-rays from black hole X-ray binary systems (BHXRBs) are investigated. The BHXRBs consist of a stellar black hole, a companion (donor) star, a BH accretion disk, a BH corona, and two jets emitted from the black hole perpendicular to the accretion disk. For their description, properties of the accretion disk, specifically the accretion disk’s inner radius Rin and the accretion disk’s temperature profile T(R), play key roles since they depend on the black hole’s dimensionless spin parameter α∗. In this work, we focus on the main reaction mechanisms taking place inside jets from which high-energy γ-rays and neutrinos are created. The intensities and integral fluxes of neutrinos and γ-rays are obtained by integrating the respective source functions. Lastly, the γ-ray absorption due to e−-e+ pair production is considered, particularly absorption from the accretion disk. For concrete applications, we have chosen the BHXRB systems MAXI J1820+070, XTE J1550-564, and XTE J1859+226.
Association of the Serotonin and Kynurenine Pathways as Possible Therapeutic Targets to Modulate Pain in Patients with Fibromyalgia
Authors: Alfaro-Rodríguez Alfonso , Reyes-Long Samuel , Roldan-Valadez Ernesto , González-Torres Maykel , Bonilla-Jaime Herlinda , Bandala Cindy , Avila-Luna Alberto , Bueno-Nava Antonio , Cabrera-Ruiz Elizabeth , Sanchez-Aparicio Pedro , González Maciel Angélica , Dotor-Llerena Ana Lilia , Cortes-Altamirano José Luis
Published: September 2024

Fibromyalgia (FM) is a disorder characterized by widespread chronic pain, significant depression, and various neural abnormalities. Recent research suggests a reciprocal exacerbation mechanism between chronic pain and depression. In patients with FM, dysregulation of tryptophan (Trp) metabolism has been identified. Trp, an essential amino acid, serves as a precursor to serotonin (5-HT), a neuromodulator that influences mood, appetite, sleep, and pain perception through the receptors 5-HT1, 5-HT2, and 5-HT3. Additionally, Trp is involved in the kynurenine pathway, a critical route in the immune response, inflammation, and production of neuroactive substances and nicotinamide adenine dinucleotide (NAD+). The activation of this pathway by pro-inflammatory cytokines, such as tumor necrosis factor α (TNF-α) and interferon gamma (IFN-γ), leads to the production of kynurenic acid (KYNA), which has neuroprotective properties, and quinolinic acid (QA), which is neurotoxic. These findings underscore the crucial balance between Trp metabolism, 5-HT, and kynurenine, where an imbalance can contribute to the dual burden of pain and depression in patients with FM. This review proposes a novel therapeutic approach for FM pain management, focusing on inhibiting QA synthesis while co-administering selective serotonin reuptake inhibitors to potentially increase KYNA levels, thus dampening pain perception and improving patient outcomes.
Improving Skin Cancer Treatment by Dual Drug Co-Encapsulation into Liposomal Systems—An Integrated Approach towards Anticancer Synergism and Targeted Delivery
Authors: Corte-Real Margarida , Veiga Francisco , Paiva-Santos Ana Cláudia , Pires Patrícia C.
Published: September 2024

Skin cancer is a high-incidence complex disease, representing a significant challenge to public health, with conventional treatments often having limited efficacy and severe side effects. Nanocarrier-based systems provide a controlled, targeted, and efficacious methodology for the delivery of therapeutic molecules, leading to enhanced therapeutic efficacy, the protection of active molecules from degradation, and reduced adverse effects. These features are even more relevant in dual-loaded nanosystems, with the encapsulated drug molecules leading to synergistic antitumor effects. This review examines the potential of improving the treatment of skin cancer through dual-loaded liposomal systems. The performed analysis focused on the characterization of the developed liposomal formulations’ particle size, polydispersity index, zeta potential, encapsulation efficiency, drug release, and in vitro and/or in vivo therapeutic efficacy and safety. The combination of therapeutic agents such as doxorubicin, 5-fluorouracil, paclitaxel, cetuximab, celecoxib, curcumin, resveratrol, quercetin, bufalin, hispolon, ceramide, DNA, STAT3 siRNA, Bcl-xl siRNA, Aurora-A inhibitor XY-4, 1-Methyl-tryptophan, and cytosine–phosphate–guanosine anionic peptide led to increased and targeted anticancer effects, having relevant complementary effects as well, including antioxidant, anti-inflammatory, and immunomodulatory activities, all relevant in skin cancer pathophysiology. The substantial potential of co-loaded liposomal systems as highly promising for advancing skin cancer treatment is demonstrated.
Perceived Needs, Barriers, and Challenges to Continuing Professional Development (CPD): A Qualitative Exploration among Hospital Pharmacists
Authors: Aldakhil Sundus , Baqar Sana Majdi , Alosaimi Bashayr , Almuzirie Rafal , Farooqui Maryam , Alsahali Saud , Almogbel Yasser
Published: September 2024

Continuing professional development (CPD) is an essential tool for healthcare professionals to remain up-to-date with the latest advancements in their field. In Saudi Arabia, pharmacists are officially registered healthcare professionals by the Saudi Commission for Health Specialties (SCFHS). To uphold their licensure, they must complete 40 h of CPD every two years. This qualitative study aimed to explore hospital pharmacists’ perceptions, barriers, and challenges of CPD, as well as their recommendations for improving CPD activities. A qualitative descriptive approach with semi-structured face-to-face interviews was employed. Using purposive sampling, 12 hospital pharmacists were interviewed. The recorded data were transcribed and analyzed using thematic analysis. Pharmacists generally showed positive perceptions of CPD, recognizing its importance for their professional development and the provision of high-quality patient care. However, some pharmacists expressed dissatisfaction with the current system. Several barriers to participation such as heavy workloads, lack of time, and limited financial support were highlighted. The primary motivations for engaging in CPD included fulfilling regulatory requirements. Workshops were the most beneficial CPD activities among others. Additionally, importance of more specialized, practice-oriented programs was highlighted. The study provides valuable insights into the needs and challenges faced by hospital pharmacists in Saudi Arabia regarding CPD. The insights gained can inform theory, policy, and practice relating to pharmacists’ CPD at both professional and governmental levels.
Channel Correlation-Based Adaptive Power Transmission for Free-Space Optical Communications
Authors: Zhao Bai-Shan , Lv Peng-Fei , Hong Yan-Qing
Published: September 2024

Free-space optical (FSO) communication has received widespread attention as a high-bandwidth, low-latency communication technique. However, the scintillation effect caused by atmospheric turbulence leads to intensity fluctuations of the transmission signal, which, in turn, affects the performance of the FSO communication system. This paper proposes a channel correlation-based adaptive power transmission for FSO communications. Based on the correlation between uplink and downlink turbulence channels, the power of the reverse transmission signal is adjusted by the fluctuation strength of the received uplink or downlink transmission signal and the channel correlation coefficient to improve the system’s performance. The proposed technique is investigated through a simulation using established uplink and downlink channels with different link distances and turbulence intensities. The simulation results show that the bit error rate (BER) performance of the proposed technique is significantly improved compared to the fixed threshold decision (FTD) technique, and it is close to the adaptive threshold decision (ATD) technique. The proposed technique provides an effective optimization scheme for FSO communications.
Molecular Dynamics Simulation and Experimental Study of the Mechanical and Tribological Properties of GNS-COOH/PEEK/PTFE Composites
Authors: Dong Zhen , Tang Henan , Yang Bin , Wang Shijie , Li Yunlong , Liu Lin
Published: September 2024

Molecular dynamics (MD) simulations were first employed to achieve the optimal sintering temperature of carboxyl-functionalized graphene (GNS-COOH)-modified polyether ether ketone (PEEK)/polytetrafluoroethylene (PTFE) composites. A model of GNS-COOH/PEEK/PTFE composites was constructed to simulate the effects of different sintering temperatures on the mechanical and tribological properties, as well as their underlying atomic mechanisms. Samples of PTFE composites were prepared and characterized through experimental methods. Results revealed that the sintering temperature significantly affects the intermolecular forces, mechanical properties, and tribological characteristics of the composites. The agglomeration of the PEEK/PTFE composite matrix was effectively mitigated by introducing GNS-COOH. When the sintering temperature was controlled at 360 °C, the compressive strength of GNS-COOH/PEEK/PTFE composites was improved compared to GNS/PEEK/PTFE composites, albeit with a slight reduction in wear resistance. This study provides a theoretical reference for the preparation process and performance evaluation of new materials.
Influence of Fiber Orientation on Mechanical Response of Jute Fiber-Reinforced Polymer Composites
Authors: Iquilio Roberto , Valín José Luis , Villalobos Kimio , Núñez Sergio , González Álvaro , Valin Meylí
Published: September 2024

The influence of fiber orientation on the mechanical behavior of a polymer matrix composite reinforced with natural jute fibers is investigated in this study. Two fiber orientation configurations are examined: the first involves woven fibers aligned in the direction of testing, while the second considers a 45° orientation. The research involves manufacturing composite plates using jute fabric with the mentioned orientations, followed by cutting rectangular specimens for tensile testing to determine which orientation yields superior properties. Displacement fields are measured using a digital image correlation technique, synchronized with load data obtained from a universal testing machine equipped with a load cell to obtain stress–strain curves for each configuration. Results indicate that 0° specimens achieve higher stress but lower strain compared to 45° specimens. This research contributes to understanding the optimal fiber alignment for enhancing the mechanical performance of fiber-reinforced polymer composites.
Deciphering the Effect of Hyaluronic Acid/Collagen Hydrogel for Pain Relief and Tissue Hydration in a Rat Model of Intervertebral Disc Degeneration
Authors: Mohd Razak Rusydi , Harizal Nur Arina Amira , Azman Mohammad Ali Zuhdi , Mohd Redzuan Najwa Syakirah , Ogaili Raed H. , Kamarrudin Ahmad Hafiz , Mohamad Azmi Muhammad Fakhrullah , Kamaruddin Nur Aqilah , Abdul Jamil Aminatul Saadiah , Mokhtar Sabarul Afian , Mohd Isa Isma Liza
Published: September 2024

Intervertebral disc (IVD) degeneration is one of the primary causes of low back pain, causing disability; hence, there is no regenerative nature of the current treatments. Hyaluronic acid (HA) was reported to facilitate tissue repair and alleviate pain. Herein, we determined the therapeutic effect of HA and type II collagen (COLII) hydrogel for tissue repair targeting pain in IVD degeneration. We implanted HA/COLII hydrogel following surgically induced disc injury at coccygeal levels in the rat tail model of pain. We assessed the efficacy of the HA/COLII hydrogel in reducing pain behaviour by using the von Frey assessment, protein expression of growth-associated protein (GAP) 43 for sensory nerve innervation, and disc hydration by magnetic resonance imaging (MRI). We observed the anti-nociceptive effect of the HA/COLII hydrogel in alleviating mechanical allodynia in rats. There was an inhibition of sensory hyperinnervation indicated by the GAP43 protein in the treatment group. We revealed an increase in T1ρ mapping of MRI, indicating that the hydrogel restored disc hydration in vivo. Our findings suggest the HA/COLII hydrogel alleviates pain behaviour, inhibits hyperinnervation and promotes disc hydration for tissue repair, implying that it is a potential candidate for the treatment of degenerative disc-associated low back pain.
Preparation and Properties of Lightweight Amphiphobic Proppant for Hydraulic Fracturing
Authors: Wang Guang , Ma Qinyue , Ren Longqiang , Hou Jirui
Published: September 2024

The wettability of the proppant is crucial in optimizing the flowback of fracturing fluids and improving the recovery of the produced hydrocarbons. Neutral wet proppants have been proven to improve the fluid flow by reducing the interaction between the fluid and the proppant surface. In this study, a lightweight amphiphobic proppant (LWAP) was prepared by coating a lightweight ceramic proppant (LWCP) with phenolic resin, epoxy resin, polytetrafluoroethylene (PTFE), and trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane (TMHFS) using a layer-by-layer method. The results indicated that the LWAP exhibited a breakage ratio of 2% under 52 MPa (7.5 K) closure stress, with an apparent density of 2.12 g/cm3 and a bulk density of 1.21 g/cm3. The contact angles of water and olive oil were 125° and 104°, respectively, changing to 124° and 96° after displacement by water and diesel oil. A comparison showed that the LWAP could transport over a significantly longer distance than the LWCP, with the length increasing by more than 80%. Meanwhile, the LWAP displayed notable resistance to scale deposition on the proppant surface compared to the LWCP. Furthermore, the maintained conductivity of the LWAP was higher than that of the LWCP after displacement by water and oil phases alternately. The modified proppant could minimize production declines during hydrocarbon extraction in unconventional reservoirs.
Preparation and Characterization of Fluorinated Acrylate and Epoxy Co-Modified Waterborne Polyurethane
Authors: Zhao Yufei , Yang Shuai , Zhang Jianjun , Xu Shaoxiong , Han Jinhui , Ma Sude
Published: September 2024

Conventional waterborne polyurethane (WPU) has poor water resistance and poor overall performance, which limits its application in outdoor coatings. A solution to this problem is urgently needed. The introduction of fluorine-containing groups can effectively improve the water resistance of WPU. In this study, a new fluorinated chain extender (HFBMA-HPA) synthesized by free radical copolymerization and epoxy resin (E-44) were used to co-modify WPU, and five waterborne fluorinated polyurethane (WFPU) emulsions with different fluorine contents were prepared by the self-emulsification method. The effects of HFBMA-HPA content on the emulsion particle properties, coating surface properties, mechanical properties, water resistance, thermal stability, and corrosion resistance were investigated. The results showed that the WFPU coating had excellent thermal stability, corrosion resistance, and mechanical properties. As the content of HFBMA-HPA increased from 0 wt% to 14 wt%, the water resistance of the WFPU coating gradually increased, the water contact angle (WCA) increased from 73° to 98°, the water absorption decreased from 7.847% to 3.062%, and the surface energy decreased from 32.8 mN/m to 22.6 mN/m. The coatings also showed impressive performances in the adhesion and flexibility tests in extreme conditions. This study provides a waterborne fluorinated polyurethane material with excellent comprehensive performance that has potential application value in the field of outdoor waterproof and anticorrosion coatings.
An Insight into the Mechanical Properties of Unidirectional C/C Composites Considering the Effect of Pore Microstructures via Numerical Calculation
Authors: Ge Jian , Chao Xujiang , Tian Wenlong , Li Weiqi , Qi Lehua
Published: September 2024

Pores are common defects generated during fabrication, which restrict the application of carbon/carbon (C/C) composites. To quantitatively understand the effects of pores on mechanical strength, this paper proposes a representative volume element model of unidirectional (UD) C/C composites based on the finite element method. The Hashin criterion and exponential degraded rule are used as the failure initiation and evolution of pyrolytic carbon matrices, respectively. Interfacial zones are characterized using the cohesive constitutive. At the same time, periodic boundary conditions are employed to study transverse tensile, compressive, and shear deformations of UD C/C composites. Predicted results are compared with the experimental results, which shows that the proposed model can effectively simulate the transverse mechanical behaviors of UD C/C composites. Based on this model, the effects of microstructural parameters including porosity, pore locations, the distance between two pores, pore clustering, and pore shapes on the mechanical strength are investigated. The results show that porosity markedly reduces the strength as porosity increases. When the porosity increases from 4.59% to 12.5%, the transverse tensile, compressive, and shear strengths decrease by 35.91%, 37.52%, and 30.76%, respectively. Pore locations, the distance between two pores, and pore clustering have little effect on the shear strength of UD C/C composites. For pore shapes, irregular pores more easily lead to stress concentration and matrix failure, which greatly depresses the bearing capacity of UD C/C composites.
Synthesis of Poly(L–lactide)–poly(ε–caprolactone)–poly(ethylene glycol) Terpolymer Grafted onto Partially Oxidized Carbon Nanotube Nanocomposites for Drug Delivery
Authors: González-Iñiguez Karla J. , Figueroa-Ochoa Edgar B. , Martínez-Richa Antonio , Cajero-Zul Leonardo R. , Nuño-Donlucas Sergio M.
Published: September 2024

Nanocomposites prepared with a terpolymer of poly(L–lactide) (PLLA)–poly(ε–caprolactone) (PCL)–poly(ethylene glycol) (PEG) and partially oxidized carbon nanotubes (CNTspo) were synthesized and characterized to evaluate their ability to act as an effective nanocarrier of the anticancer drug methotrexate. The homopolymers of PLLA and PCL were synthesized through ring-opening polymerization (ROP) and characterized through gel permeation chromatography (GPC). The PLLA–PCL–PEG terpolymers were synthesized through a four-step chemical route using oxalyl chloride as a linker agent and analyzed with 1H–NMR, 13C–NMR, and FTIR spectroscopies. Additionally, the nanocomposites were characterized through FTIR, and X-ray photoelectron spectroscopy (XPS), as well as the differential scanning calorimetry (DSC) technique. XPS analysis revealed that PLLA–PCL–PEG terpolymer chains are grafted onto CNTspo. Moreover, evaluations through FTIR and DSC strongly suggest that the PCL-rich domains are preferentially oriented toward CNTspo. The release tests exhibited a “burst effect” profile, which was more evident in the terpolymers than in the nanocomposites. Five models were used to assess methotrexate’s in vitro release. For the nanocomposites, the best fit to the experimental data was obtained using the first-order model, whereas the results obtained from the Korsmeyer–Peppas model indicated that Fickian diffusion drives methotrexate’s release.
Experimental and Simulation Study on Failure of Thermoplastic Carbon Fiber Composite Laminates under Low-Velocity Impact
Authors: Yang Lei , Huang Xiaolin , Liao Zhenhao , Wei Zongyou , Zou Jianchao
Published: September 2024

Numerous studies have demonstrated that under low-velocity, low-energy impact conditions, although the surface damage to fiber-reinforced composite laminates may be minimal, significant internal damage can occur. Consequently, a progressive damage finite element model was specifically developed for thermoplastic carbon fiber-reinforced composite laminates subjected to low-speed impact loads, with the objective of analyzing the damage behavior of laminates under impacts of varying energy levels. The model utilizes a three-dimensional Hashin criterion for predicting intralayer damage initiation, with cohesive elements based on bilinear traction–separation law for predicting interlaminar delamination initiation, and incorporates a damage constitutive model based on equivalent displacement to characterize fiber damage evolution, along with the B-K criterion for interlaminar damage evolution. The impact response of laminates at energy levels of 5 J, 10 J, 15 J, 20 J, and 25 J was analyzed through numerical simulation, drop-hammer experiments, and XCT non-destructive testing. The results indicated that the simulation outcomes closely correspond with the experimental findings, with both the predicted peak error and absorbed energy error maintained within a 5% margin, and the trends of the mechanical response curves aligning closely with the experimental data. The damage patterns predicted by the numerical simulations were consistent with the results obtained from XCT scans. The study additionally revealed that the impact damage of the laminates primarily stems from interlaminar delamination and intralayer tensile failure. Initial damage typically presents as internal delamination; hence, enhancing interlaminar bonding performance can significantly augment the overall load-bearing capacity of the laminate.
Modification of the Surface Crystallinity of Polyphenylene Sulfide and Polyphthalamide Treated by a Pulsed-Arc Atmospheric Pressure Plasma Jet
Authors: Anagri Abdessadk , Ben Saïd Sarab , Bazin Cyrille , Arefi-Khonsari Farzaneh , Pulpytel Jerome
Published: September 2024

Atmospheric plasma jets generated from air or nitrogen using commercial sources with relatively high energy densities are commonly used for industrial applications related to surface treatments, especially to increase the wettability of polymers or to deposit thin films. The heat fluxes to which the substrates are subjected are typically in the order of 100–300 W/cm2, depending on the treatment conditions. The temperature rise in the treated polymer substrates can have critical consequences, such as a change in the surface crystallinity or even the surface degradation of the materials. In this work, we report the phase transitions of two semicrystalline industrial-grade polymer resins reinforced with glass fibers, namely polyphenylene sulfide (PPS) and polyphthalamide (PPA), subjected to plasma treatments, as well as the modeling of the associated heat transfer phenomena using COMSOL Multiphysics. Depending on the treatment time, the surface of PPS becomes more amorphous, while PPA becomes more crystalline. These results show that the thermal history of the materials must be considered when implementing surface engineering by this type of plasma discharge.
Evaluation of Reservoir Damage by Hydrothermal Fluid from Clay Metamorphism, Particle Migration, and Heavy-Component Deposition in Offshore Heavy Oilfields
Authors: Zheng Zuhao , Zhang Lu , Yin Hongchao , Liu Dong , He Wei , Shui Leilei , Wang Ning , Chen Hao , Yang Shenglai , Zhang Yiqi
Published: September 2024

Marine heavy-oil reserves are enormous, and thermal recovery technology is one of the most effective ways to utilize them. However, steam as a high-energy external fluid will affect the geological characteristics of the reservoir. In this paper, the sensitivity of the reservoir was analyzed in terms of the high-temperature metamorphic characteristics of clay minerals and the coupling damage of particle migration and heavy component deposition. Firstly, long-core cyclic steam stimulation experiments were conducted using supersaturated steam, saturated steam, and superheated steam to quantify the differences in oil recovery capabilities. Subsequently, the variation characteristics of clay components in the core under different steam temperatures were analyzed by X-ray diffraction spectroscopy. Finally, the influence of particle migration and heavy-component deposition on reservoir permeability was clarified through displacement experiments. The results show that the recovery of superheated steam is more than 12% higher than that of supersaturated steam, and the throughput cycle is effectively shortened. In the laboratory, only the clay metamorphism due to superheated steam was more effective, and the metamorphism was mainly concentrated in kaolinite and monazite. Particle migration causes little damage to the reservoir, but the formation of particle migration coupled with heavy-component deposition can lead to more than 30% of the reservoir becoming damaged.
Monitoring and Predicting Air Quality with IoT Devices
Authors: Banciu Claudia , Florea Adrian , Bogdan Razvan
Published: September 2024

The growing concern about air quality and its influence on human health has prompted the development of sophisticated monitoring and forecast systems. This article gives a thorough investigation into forecasting the air quality index (AQI) with an Internet of Things (IoT) device that analyzes temperature, humidity, PM10, and PM2.5 levels. The dataset used for this analysis comprises 5869 data points across six critical parameters essential for accurate air quality prediction. The data from these sensors is sent to the ThingSpeak cloud platform for storage and preliminary analysis. The system forecasts AQI using a TensorFlow-based regression model, delivering real-time insights. The combination of IoT technology and machine learning improves the accuracy and responsiveness of air quality monitoring systems, making it a useful tool for environmental management and public health protection. This work presents comparatively the effectiveness of feedforward neural network models trained with the ‘adam’ and ‘RMSprop’ optimizers over different epochs, as well as the machine learning algorithm random forest with varying numbers of estimators to forecast AQI. The models were trained using both types of regression analysis: linear regression and random forest regression. The findings show that the model achieves a high degree of accuracy, with the predictions closely aligning with the actual AQI values, thus having the potential to significantly reduce the negative health impact associated with poor air quality, protecting public health and alerting users when pollution levels are higher than allowed. Specifically, the random forest model with 100 estimators delivers the best overall performance for both AQI 10 and AQI 2.5, achieving the lowest Mean Absolute Error (MAE) of 0.2785 for AQI 10 and 0.2483 for AQI 2.5. This integration of IoT technology and advanced predictive analysis addresses the significant worldwide issue of air pollution by identifying the pollution hotspots and allowing decision-makers for quick reactions, and the development of effective strategies to reduce pollution sources.
Study on Sealing Performance of Spring-Embedded Shoulder Protection Packer Rubber Cylinder
Authors: Li Jinghui , Wu Chunhong , Li Mingji , Wang Chengwen
Published: September 2024

Oil extraction is shifting towards high-temperature and high-pressure environments, which leads to the deterioration of the rubber material used in packer rubber cylinders, ultimately resulting in sealing failure. Hence, we propose enhancing the configuration of the rubber cylinder by incorporating a composite material consisting of metal and rubber. Additionally, we suggest integrating springs at the shoulders to fabricate a spring-embedded shoulder protection packer rubber cylinder. ABAQUS 2023 software was employed to simulate the packer setting process, investigating the variations in compression distance between a conventional packer rubber cylinder and a spring-embedded shoulder protection packer rubber cylinder. The results showed that at 25 °C and 177 °C, the compression distance of the fully seated spring-embedded shoulder protection packer rubber cylinder was reduced by 3% compared to the traditional packer rubber, Mises stress was reduced by 14%, and the sealing performance evaluation coefficient K of the rubber cylinder was increased by 2% to 10%.The stress in the spring-embedded shoulder protection packer rubber cylinder is primarily concentrated between the spring and the wire mesh, effectively ensuring the performance of the rubber cylinder and mitigating any potential decrease in sealing performance caused by internal stress concentration. The spring-embedded protective rubber cylinder will not experience shoulder protrusion during the sealing process. The incorporation of a spring-embedded shoulder protection mechanism in the packer rubber cylinder enhances the contact stress between the rubber cylinder and casing tube, mitigates stress concentration within the rubber cylinder, resolves shoulder protrusion issues, and ultimately improves both sealing performance and service life.
The Role of the Church in Postcolonial African Burial Rituals in Collins Chabane Municipality: A Pastoral Perspective
Authors: Hove Rabson
Published: September 2024

Death is a painful reality that strikes and affects all human beings. Death knows no boundaries, race, age, gender, belief system or status. It affects the family; the social, political and economic networks of the deceased and the community at large. Death comes with different challenges that require coping mechanisms. While Africans from all walks of life use different approaches to help the bereaved deal with death and loss, the church has become the biggest role player in attending to this crisis. Although the church is a latecomer in the lives of African people in general, for the people of Collins Chabane Municipality in particular, it is given priority when death strikes. This article seeks to articulate how the church has become central to the death and burial rituals in that municipality. To that end, the researcher conducted a review of data collected through individual and focus group interviews carried out with traditional community leaders (local chiefs) in the municipality on the theme: The erosion of postcolonial African funeral traditions in rural South Africa (Limpopo).
Reconstruction of Coal Mining Subsidence Field by Fusion of SAR and UAV LiDAR Deformation Data
Authors: Yang Bin , Du Weibing , Zou Youfeng , Zhang Hebing , Chai Huabin , Wang Wei , Song Xiangyang , Zhang Wenzhi
Published: September 2024

The geological environment damage caused by coal mining subsidence has become an important factor affecting the sustainable development of mining areas. Reconstruction of the Coal Mining Subsidence Field (CMSF) is the key to preventing geological disasters, and the needs of CMSF reconstruction cannot be met by solely relying on a single remote sensing technology. The combination of Unmanned Aerial Vehicle (UAV) and Synthetic Aperture Radar (SAR) has complementary advantages; however, the data fusion strategy by refining the SAR deformation field through UAV still needs to be updated constantly. This paper proposed a Prior Weighting (PW) method based on Satellite Aerial (SA) heterogeneous remote sensing. The method can be used to fuse SAR and UAV Light Detection and Ranging (LiDAR) data for ground subsidence parameter inversion. Firstly, the subsidence boundary of Differential Interferometric SAR (DInSAR) combined with the large gradient subsidence of Pixel Offset Tracking (POT) was developed to initialize the SAR preliminary CMSF. Secondly, the SAR preliminary CMSF was refined by UAV LiDAR data; the weights of SAR and UAV LiDAR data are 0.4 and 0.6 iteratively. After the data fusion, the subsidence field was reconstructed. The results showed that the overall CMSF accuracy improved from ±144 mm to ±51 mm. The relative errors of the surface subsidence factor and main influence angle tangent calculated by the physical model and in situ measured data are 1.3% and 1.7%. It shows that the proposed SAR/UAV fusion method has significant advantages in the reconstruction of CMSF, and the PW method contributes to the prevention and control of mining subsidence.
Utilizing Machine Learning and Multi-Station Observations to Investigate the Visibility of Sea Fog in the Beibu Gulf
Authors: Huang Qin , Zeng Peng , Guo Xiaowei , Lyu Jingjing
Published: September 2024

This study utilizes six years of hourly meteorological data from seven observation stations in the Beibu Gulf—Qinzhou (QZ), Fangcheng (FC), Beihai (BH), Fangchenggang (FCG), Dongxing (DX), Weizhou Island (WZ), and Hepu (HP)—over the period from 2016 to 2021. It examines the diurnal variations of sea fog occurrence and compares the performance of three machine learning (ML) models—Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Categorical Boosting (CatBoost)—in predicting visibility associated with sea fog in the Beibu Gulf. The results show that sea fog occurs more frequently during the nighttime than during the daytime, primarily due to day-night differences in air temperature, specific humidity, wind speed, and wind direction. To predict visibility associated with sea fog, these variables, along with temperature-dew point differences (Ta−Td), pressure (p), month, day, hour, and wind components, were used as feature variables in the three ML models. Although all the models performed satisfactorily in predicting visibility, XGBoost demonstrated the best performance among them, with its predicted visibility values closely matching the observed low visibility in the Beibu Gulf. However, the performance of these models varies by station, suggesting that additional feature variables, such as geographical or topographical variables, may be needed for training the models and improving their accuracy.
Review of Satellite Remote Sensing of Carbon Dioxide Inversion and Assimilation
Authors: Hu Kai , Feng Xinyan , Zhang Qi , Shao Pengfei , Liu Ziran , Xu Yao , Wang Shiqian , Wang Yuanyuan , Wang Han , Di Li , Xia Min
Published: September 2024

With the rapid development of satellite remote sensing technology, carbon-cycle research, as a key focus of global climate change, has also been widely developed in terms of carbon source/sink-research methods. The internationally recognized “top-down” approach, which is based on satellite observations, is an important means to verify greenhouse gas-emission inventories. This article reviews the principles, categories, and development of satellite detection payloads for greenhouse gases and introduces inversion algorithms and datasets for satellite remote sensing of XCO2. It emphasizes inversion methods based on machine learning and assimilation algorithms. Additionally, it presents the technology and achievements of carbon-assimilation systems used to estimate carbon fluxes. Finally, the article summarizes and prospects the future development of carbon-assimilation inversion to improve the accuracy of estimating and monitoring Earth’s carbon-cycle processes.
Assessing the Impact of Agricultural Practices and Urban Expansion on Drought Dynamics Using a Multi-Drought Index Application Implemented in Google Earth Engine: A Case Study of the Oum Er-Rbia Watershed, Morocco
Authors: Serbouti Imane , Chenal Jérôme , Pradhan Biswajeet , Diop El Bachir , Azmi Rida , Abdem Seyid Abdellahi Ebnou , Adraoui Meriem , Hlal Mohammed , Bounabi Mariem
Published: September 2024

Drought monitoring is a critical environmental challenge, particularly in regions where irrigated agricultural intensification and urban expansion pressure water resources. This study assesses the impact of these activities on drought dynamics in Morocco’s Oum Er-Rbia (OER) watershed from 2002 to 2022, using the newly developed Watershed Integrated Multi-Drought Index (WIMDI), through Google Earth Engine (GEE). WIMDI integrates several drought indices, including SMCI, ESI, VCI, TVDI, SWI, PCI, and SVI, via a localized weighted averaging model (LOWA). Statistical validation against various drought-type indices including SPI, SDI, SEDI, and SMCI showed WIMDI’s strong correlations (r-values up to 0.805) and lower RMSE, indicating superior accuracy. Spatiotemporal validation against aggregated drought indices such as VHI, VDSI, and SDCI, along with time-series analysis, confirmed WIMDI’s robustness in capturing drought variability across the OER watershed. These results highlight WIMDI’s potential as a reliable tool for effective drought monitoring and management across diverse ecosystems and climates.
Accurately Measuring the Infrared Spectral Emissivity of Inconel 601, Inconel 625, and Inconel 718 Alloys during the Oxidation Process
Authors: Li Longfei , Wang Fayu , Gao Jiaying , Yu Kun , Wang Lan , Liu Yufang
Published: September 2024

Accurate measurement of the infrared spectral emissivity of nickel-based alloys is significant for applications in aerospace. The low thermal conductivity of these alloys limits the accuracy of direct emissivity measurement, especially during the oxidation process. To improve measurement accuracy, a surface temperature correction method based on two thermocouples was proposed to eliminate the effect of thermal conductivity changes on emissivity measurement. By using this method, the infrared spectral emissivity of Inconel 601, Inconel 625, and Inconel 718 alloys was accurately measured during the oxidation process, with a temperature range of 673–873 K, a wavelength range of 3–20 μm, and a zenith angle range of 0–80°. The results show that the emissivity of the three alloys is similar in value and variation law; the emissivity of Inconel 718 is slightly less than that of Inconel 601 and Inconel 625; and the spectral emissivity of the three alloys strongly increases in the first hour, whereafter it grows gradually with the increase in oxidation time. Finally, Inconel 601 has a lower emissivity growth rate, which illustrates that it possesses stronger oxidation resistance and thermal stability. The maximum relative uncertainty of the emissivity measurement of the three alloys does not exceed 2.6%, except for the atmospheric absorption wavebands.
First in-Lab Testing of a Cost-Effective Prototype for PM2.5 Monitoring: The P.ALP Assessment
Authors: Fanti Giacomo , Borghi Francesca , Wolfe Cody , Campagnolo Davide , Patts Justin , Cattaneo Andrea , Spinazzè Andrea , Cauda Emanuele , Cavallo Domenico Maria
Published: September 2024

The goal of the present research was to assess, under controlled laboratory conditions, the accuracy and precision of a prototype device (named ‘P.ALP’: Ph.D. Air-quality Low-cost Project) developed for PM2.5 concentration level monitoring. Indeed, this study follows a complementary manuscript (previously published) focusing on the in-field evaluation of the device’s performance. Four P.ALP prototypes were co-located with the reference instrument in a calm-air aerosol chamber at the NIOSH laboratories in Pittsburgh, PA (USA), used by the Center for Direct Reading and Sensor Technologies. The devices were tested for 10 monitoring days under several exposure conditions. To evaluate the performance of the prototypes, different approaches were employed. After the data from the devices were stored and prepared for analysis, to assess the accuracy (comparing the reference instrument with the prototypes) and the precision (comparing all the possible pairs of devices) of the P.ALPs, linear regression analysis was performed. Moreover, to find out the applicability field of this device, the US EPA’s suggested criteria were adopted, and to assess error trends of the prototype in the process of data acquisition, Bland–Altman plots were built. The findings show that, by introducing ad hoc calibration factors, the P.ALP’s performance needs to be further implemented, but the device can monitor the concentration trend variations with satisfying accuracy. Overall, the P.ALP can be involved in and adapted to a wide range of applications because of the inexpensive nature of the components, the small dimensions, and the high data storage capacity.