High Enhancement Research Articles

The Efficacy of Mnemonic Strategies in Improving the Basic Multiplication Facts Retrieval

The current quasi-experimental study aims to investigate the efficacy of mnemonic strategies (Visual imagery and Story-linking) to improve the basic multiplication fact retrieval of grade 3 students with mathematics difficulties. The authors employed a quantitative approach within the matching-only pretest-post-test control group design to analyze the data on 206 subjects, of whom 78 exhibited mathematical difficulties. The study was conducted in eight inclusive primary schools in Purwakarta City, Indonesia. The research findings indicated that the N-gain acquisition of students in the experimental group (0.38) outperformed students in the control group (0.11). Similarly, the N-gain acquisition of students with mathematics difficulties in the experimental group (0.26) indicated a higher enhancement than those in the control group (0.08). Overall, the mnemonic strategies improved the students’ retrieval of basic multiplication facts on students with and without mathematics difficulties. However, mnemonic strategies have successfully achieved two of the Sustainable Development Goals 4 (SDG 4) by the 2030 Agenda for Sustainable Development on ensuring students with disabilities as one of the vulnerable groups, have equal access to education and guaranteeing both male and females are literate and numerically literate. These findings have practical implications for educators, providing them with actionable insights to develop effective teaching strategies for students with mathematics difficulties.

Performance enhancement of porous clay cooler for BIPV applications using hollowed clay structures and metallic extended fins as evaporation and thermal conductivity enhancers

This paper investigates the employing of a passive evaporative cooling approach to mitigate the temperature rise of PV panels within building-integrated photovoltaic (BIPV) systems. The investigation explores enhancing the heat transfer capabilities of composite clay layers by incorporating thermal conductive materials such as iron-oxide and zinc-oxide. This enhancement aimed to improve the overall thermal properties of the composite clay structures, thereby boosting heat transfer rates. Additionally, two distinct designs were evaluated as well: one integrating hollowed clay layer and the other featuring a clay layer with extended fins to enhance both heat and mass transfer rates within the evaporative porous clay structure. A series of experiments conducted under real conditions using prototyped building rooms to simulate real BIPV systems to assess the cooling performance of the presented scenarios. The results revealed that the hollowed clay layer achieved the most substantial decrease in PV panel temperature, with a reduction of 16.5 % compared to the findings with a solid clay layer. In contrast, the composite Iron-oxide/clay layer demonstrated the smallest decrease in PV temperature at 11 %. Moreover, utilizing the hollowed clay structure led to a 6.3 % increase in average PV output power, as well as around 4.5 % enhancement in average photovoltaic’s efficiency compared to the outcomes observed with the solid clay layer. Moreover, incorporating the hollowed clay layer resulted in the most significant decrease in the building's annual load, achieving a reduction of 79.6 %. This signifies approximately a 2 % higher enhancement in cooling capabilities compared to utilizing solid clay layer. Further, the cost of electricity production decreased by 7.7 % (from 0.104 $/kWh to 0.096 $/kWh) following the incorporation of the hollowed clay layer, while the payback time was reduced by roughly 0.8 years compared to utilizing the solid clay layer and by 1.7 years in comparison to the non-cooled BIPV system.

Understanding daily and momentary drinking motives among transgender and gender diverse adults

Background Transgender and gender diverse (TGD) adults may be at increased risk for alcohol use due to gender minority stress (GMS) and specific drinking motives. Aim The current study evaluated the relations between GMS and resilience, drinking motives, and alcohol outcomes among TGD adults. Methods Twenty-five primarily White TGD adults (7 transgender men, 7 transgender women, and 11 gender diverse) who were 19 years of age or older (mean: 32.60; SD: 10.82), lived in Canada, and drank regularly were prompted to complete surveys multiple times per day indexing drinking motives, GMS and resilience factors, contexts, and alcohol use and craving. Multilevel models examined predictors of each drinking motive and relations between drinking motives and alcohol outcomes at the daily and momentary levels. Results Days with increased GMS corresponded with increased social (p<.05) and conformity motives (p<.01). Days with increased resilience also corresponded with elevated social (p<.01) and conformity (p<.05) motives. Days with higher enhancement and social motives predicted increased alcohol use (ps<.01). All momentary motives were elevated when participants reported higher momentary resilience (p<.001). Significant associations between drinking motives, contexts, and alcohol craving were also evident. Discussion GMS and certain drinking motives may contribute to increased alcohol use and craving among TGD adults. Findings encourage the development of gender-inclusive interventions that address GMS and specific drinking motives to support a reduction in this population’s alcohol use.

Self-Administered Acupressure for Probable Knee Osteoarthritis in Middle-Aged and Older Adults

The effects of self-administered acupressure (SAA) on knee osteoarthritis (OA) pain remain unclear. To evaluate the effectiveness of SAA taught via a short training course on reducing knee OA pain in middle-aged and older adults. This randomized clinical trial was conducted among community-dwelling individuals in Hong Kong who were aged 50 years or older with probable knee OA from September 2019 to May 2022. The intervention included 2 training sessions for SAA with a brief knee health education (KHE) session, in which participants practiced acupressure twice daily for 12 weeks. The control group (KHE only) received only education about maintaining knee health on the same schedule and duration. The primary outcome was the numerical rating scale (NRS) pain score at 12 weeks. Other outcomes included Western Ontario and McMaster University Osteoarthritis Index, Short Form 6 Dimensions (SF-6D), Timed Up and Go, and Fast Gait Speed tests. A total of 314 participants (mean [SD] age, 62.7 [4.5] years; 246 [78.3%] female; mean [SD] knee pain duration, 7.3 [7.6] years) were randomized into intervention and KHE-only groups (each 157). At week 12, compared with the KHE-only group, the intervention group had a significantly greater reduction in NRS pain score (mean difference [MD], -0.54 points; 95% CI, -0.97 to -0.10 points; P = .02) and higher enhancement in SF-6D utility score (MD, 0.03 points; 95% CI, 0.003 to 0.01 points; P = .03) but did not have significant differences in other outcome measures. The cost-effectiveness acceptability curve demonstrated a greater than 90% probability that the intervention is cost-effective at a willingness to pay threshold of 1 GDP per capita. In this randomized clinical trial, SAA with a brief KHE program was efficacious and cost-effective in relieving knee pain and improving mobility in middle-aged and older adults with probable knee OA. ClinicalTrials.gov Identifier: NCT04191837.

The multiple enhancements of deep eutectic solvent on cellulase significantly improve the saccharification efficiency of lignocellulosic biomass

The introduction of specific choline chloride (ChCl)- and betaine (Bet)-based deep eutectic solvents (DESs) into the conventional acetic acid–sodium acetate solution led to a significant increase in cellulase activity and stability. In particular, a higher enhancement in β-glucosidase activity was obtained, which plays a key role in improving cellulase function. The DESs prolonged the half-life of cellulase. The addition of 10 % (v/v) ChCl/1,3-propanediol (1:2) and 5 % (v/v) Bet/glycerol (1:2) resulted in the most significant improvement, with the half-life of cellulase reaching three times the initial half-life value. The above both DESs allowed the cellulase to maintain an excellent level of activity over time, even after 72 h. The DESs tightened the structure of the enzyme by changing its secondary structure, which had a stabilizing effect on the overall conformation. The density functional theory calculations of DESs revealed that the DES with a more stable structure more effectively protected the active conformation. The molecular dynamics simulation on β-glucosidase indicated that the hydrogen bond donor end of the DES primarily formed hydrogen bonds with the enzyme, which induced a spatially compact conformation by increasing the α-helix content while reducing the β-sheet content. It also restricted the movement of amino acids, particularly stabilizing the active site, and increased the hydrophilic region, thereby enhancing enzyme activity and stability. In addition, the DES formed a protective layer that prevented the unproductive adsorption of lignin on the enzymes during the hydrolysis of lignocellulosic feedstocks. These multiple improvements provided by DESs significantly increased the enzymatic saccharification efficiency of corn stover and poplar.

Plaque enhancement predicts recurrence in acute ischemic stroke patients with large artery intracranial atherosclerosis

BackgroundThe association between the degree of plaque enhancement and ischemic brain stroke recurrence remains unclear. We aimed to establish models to predict plaque enhancement and stroke recurrence. MethodsSeventy-eight participants with acute ischemic brain stroke due to intracranial arterial stenosis were recruited and divided into high enhancement (HE) and non-HE groups. The relationship between imaging characteristics (degree of stenosis, minimal lumen area, intraplaque hemorrhage, and plaque burden) and the degree of plaque contrast enhancement was analyzed. Inflammatory cytokine expression was examined by flow cytometry. Independent predictors of stroke recurrence were investigated via multivariate Cox proportional hazards regression analysis. Nomogram was used to construct a prediction model. Harrell's concordance indices (c-indices) and calibration curves were used to assess the discrimination of the nomogram. A risk prediction nomogram for prognosis was constructed. ResultsThirty-three participants were assigned to the HE group and 45 to the non-HE group. The degree of stenosis and plaque burden in the HE group was higher than that in the non-HE group (P<0.05). Multiple linear regression analysis showed the degree of stenosis was associated with HE (β=0.513; P=0.000). After adjusting for confounding factors, age (HR=1.115; 95%CI=1.034–1.203, P=0.005) and HE plaques (HR=10.457; 95%CI=1.176–93.018; P=0.035) were independent risk factors of stroke recurrence, whereas cytokine levels were not statistically significant between two group. ConclusionsHE of intracranial atherosclerosis plaques is an independent factor for ischemic brain stroke recurrence.

Dynamic mechanical analysis for assessment of carbon fillers in glass fiber epoxy composites

AbstractThe effect of incorporation of micron sized aluminum trihydrate, multi‐walled carbon nanotubes, and graphene nano platelets into glass fiber reinforced epoxy matrix is investigated using dynamic mechanical analysis. The objective of the investigation was to develop polymer central core of high temperature low sag transmission conductor. The effect of individual and hybrid carbon fillers on the viscoelastic properties of the epoxy composites is investigated and discussed. The storage modulus of the glass reinforced epoxy increases by 20% at room temperature due to incorporation of carbon nanofillers. In glass transition region, the increase is higher between 40% and 60% and it varies up to 90% in the rubbery region. Key attributes of carbon filler addition are limited enhancement of storage modulus at room temperature, higher enhancement over glassy, glass transition, and rubbery regions. The carbon fillers extend the temperature range of the glassy region. The cross‐link density, filler efficiency, and degree of entanglement of fibers are estimated to understand the implications of the carbon fillers on the viscoelastic properties. The loss modulus peak of glass epoxy composite increases from 2800 to 3900 MPa with carbon fillers and the increase in glass transition temperature is 47°C. Incorporation of carbon fillers leads to increase of damping factor peak from 0.2 to 0.28. Cole–Cole plots have established the inherent heterogeneity of epoxy systems due to the presence of carbon fillers. Prediction models for storage modulus and damping factor have been proposed to highlight the influence of geometry and size of carbon filler.

Simultaneous charging and discharging of metal foam composite phase change material in triplex-tube latent heat storage system under various configurations

Abstract Phase change material (PCM) has high latent heat on one hand albeit low thermal conductivity on the other hand which restricts its utilization in thermal energy storage applications. Therefore, to improve thermal performance of PCM, various techniques have been employed. This numerical work intends to estimate the effect of copper metal foam (MF) in the seven various configurations (M1–M7) of triple-tube heat exchanger (TTHX) under simultaneous charging and discharging (SCD) conditions using heat transfer fluids (HTF) both the sides. Five distinct configurations with equal volumes of PCM and composite PCM (CPCM) have been considered for optimization standpoint. RT55 (melting temperature = 327 K) is taken as PCM. Based on thermo-physical properties of PCM and thermal boundary conditions on the heated tube, the dimensionless controlling parameters such as the Rayleigh number (Ra), Prandtl number (Pr), and Stefan number (Ste) were taken as 1.79 × 105, 30, and 0.21, respectively. Typical results on melt fraction, latent heat storage, temperature contours, and steady-state melt fraction and corresponding melting time have been reported. Performance yielded by all the configurations was compared for a fixed duration of 2 h. The positioning of MF largely affects the heat transfer mechanism in the latent heat storage unit. Results show that the bottom-side positioning of MF can boost the heat storage due to enhanced buoyancy-induced convection. Among all the models, M3 predicts the highest steady-state melt fraction ( λ $\lambda $ ss ≈ 0.62) in the shortest steady-state melting time (t ss ≈ 66 min), followed by model M6 (λ ss ≈ 0.58, t ss ≈ 65 min). The optimized design (model M3) shows ∼75 % latent heat storage enhancement than pure PCM (M1) case. Interestingly, one may also achieve ∼17.2 % higher enhancement using model M3 than M2 but with only half of the mass of MF than that used in full porous configuration (M2).

Large SYBR Green I fluorescence enhancement for label-free aptamer-based detection of estradiol

Estradiol (E2) and related estrogens are emerging environmental contaminants that may adversely affect the health of humans, animals, and ecosystems. Many aptamers have been reported for the detection of E2, and our lab recently selected a series of high-affinity and short DNA aptamers that showed various binding orientations to E2, leading to different selectivity patterns. In this work, we report that using SYBR Green I (SGI) as a fluorescence probe, up to 200% fluorescence increase was achieved upon titration of E2 to these aptamers. Such enhancement was the highest among all reported small molecule binding aptamers using SGI for signal generation, although some metal-binding DNA can achieve even higher enhancement. By gradually shortening the stem region of an E2 binding aptamer, we concluded that the enhanced fluorescence was from the aptamer binding pocket upon target binding instead of from the duplexed stem region. Comparison was also made with a few other aptamers including those for caffeine, quinine, uric acid and cortisol, and none of them showed more than 20% fluorescence change. Using the SGI method, the detection limit was calculated to be 2.4 nM E2. We attributed the large fluorescence enhancement to the hydrophobic nature of E2 and the high-affinity binding of the aptamers. This study provides insights into the aptamers that can use SGI for their binding assays and biosensor development.

Response of the American equatorial ionization anomaly to 2016 Arctic sudden stratospheric warming events

Apart from the rapid ionospheric response to geomagnetic forcing originating from the Sun during extreme space weather events, forcing from the lower atmosphere below still exerts a significant influence on the ionosphere during quiet-time conditions. This study examines the ionospheric response of the equatorial ionization anomaly (EIA) in the American sector to the combined influence of the cascades of sudden stratospheric warming (SSW) events and the geomagnetic storms that coexisted with them during the period of January–March 2016. We adopted a multi-instrument and multi-modeling approach with the study locations spanning ±40° geomagnetic latitudes. Our results showed a hemispheric asymmetry in the total electron content and change in total electron content (ΔTEC) distribution with higher enhancement clearly visible in the Northern Hemisphere in comparison to the Southern Hemisphere (NH). Semidiurnal signatures were observed in both ΔTEC and equatorial electrojet parameters for some days. The double-peak zonal mean zonal wind amplitude days supported the formation of the reverse fountain effects. The different SSW peak temperature days also showed either positive or negative ionospheric response. Generally, orientation of the prompt penetration electric field (PPEF) and their strengths at either daytime or nighttime played a weak role in the ionosphere response during some of the geomagnetic storms. The negative and positive ionospheric responses under geomagnetic storm conditions were ascribed to changes in the composition of the thermosphere, prompt penetration electric field (PPEF), and traveling atmospheric disturbances (TADs).

Supporting Electrolyte Manipulation for Simple Improvement of the Sensitivity of Trace Vanadium(V) Determination at a Lead-Coated Glassy Carbon Electrode.

The paper presents a very simple way to extremely improve the sensitivity of trace V(V) determination. The application of a new supporting electrolyte composition (CH3COONH4, CH3COOH, and NH4Cl) instead of the commonly used acetate buffer (CH3COONa and CH3COOH) significantly enhanced the adsorptive stripping voltammetric signal of vanadium(V) at the lead-coated glassy carbon electrode (GCE/PbF). A higher enhancement was attained in the presence of cupferron as a complexing agent (approximately 10 times V(V) signal amplification) than in the case of chloranilic acid and bromate ions (approximately 0.5 times V(V) signal amplification). Therefore, the adsorptive stripping voltammetric system with the accumulation of V(V)-cupferron complexes at -1.1 V for 15 s in the buffer solution (CH3COONH4, CH3COOH, and NH4Cl) of pH = 5.6 ± 0.1 was selected for the development of a simple and extremely sensitive V(V) analysis procedure. Under optimized conditions, the sensitivity of the procedure was 6.30 µA/nmol L-1. The cathodic peak current of V(V) was directly proportional to its concentration in the ranges of 1.0 × 10-11 to 2.0 × 10-10 mol L-1 and 2.0 × 10-10 to 1.0 × 10-8 mol L-1. Among the electrochemical procedures, the lowest detection limit (2.8 × 10-12 mol L-1) of V(V) was obtained for the shortest accumulation time (15 s). The high accuracy of the procedure was confirmed on the basis of the analysis of certified reference material (estuarine water) and river water samples.

Mix Procedure of Ultra-High Performance Concrete Containing Nano-Silica; Advantages And Challenges To Achieve Required Characteristics

The paper describes the mix method and the results of the influence of nanoparticles of nano silica (NS) (d ≈ 65 nm) on the Ultra-High performance Concrete (UHPC) matrix properties. Five different contents of NS particles were applied: 0, 0.5, 1, 1.5, and 2 wt.% by weight of cement. The studies regarding different physical and mechanical parameters of cementitious composite matrix specimens such as water absorption, porosity, compressive strength and flexural strength. Structural properties have been carried out and the results of these studies are presented and discussed. It was shown that the nanoparticles in the amounts of 1-2 wt.% can influence the cement hydration process and thereby enhance the compressive strength of cementitious composite. The higher enhancement was obtained during the first three days of hardening due to so called filling effect. In the following stage of hydration, the strengthening effect diminished. This phenomenon was convergent with the XRD analysis, which proved that the nanoparticles react with the cement paste components.

Numerical analysis of multiple phase change materials based heat sink with angled thermal conductivity enhancer

Phase change materials (PCM) RT-28HC, RT-35HC, and RT-44HC with three different melting temperatures, 29 °C, 36 °C, and 44 °C, with similar thermal properties, are considered. The PCM is oriented from the left to right side of the heat sink in its increasing order. The fins are attached to the heat sink longitudinally, and its orientation effects are studied low (100–500 W/m2) and high (1000–5000 W/m2) heat fluxes applied on the horizontal bottom surface of the heat sink. A 2D model is developed using ANSYS Fluent 19, and the fin orientation effects are investigated numerically. The orientation of fins at different angles such as 0°, +15°, +30°, +45°, +60°,-15°,-30°,-45°, −60° are considered. The effect of fins on the charging cycle is assessed by comparing a single and double PCM heat sink. Three initial conditions are investigated by altering the initial temperature 300 K, 303 K, and 310 K. At increasing heat input, the negative angled fins possess a higher melting rate. For different initial conditions, −60° provides higher enhancement, and +60° possesses prolonged melting for almost all cases. The performance of a triple PCM design is compared with single and double PCM counterparts under similar conditions.

Multi-scale analysis of the strengthening mechanism of functionalized graphene as reinforcement in cement composites

This paper explored the impact of graphene oxides used as cement composites reinforcing materials on the mechanical properties of samples. In the direct method, graphene oxide (GO) was incorporated into the mortar in different dosages, and two GOs (GO-C and GO-N, with carboxyl and amino groups respectively) greatly improved the mechanical performance of mortar. The test results show that GO promoted the hydration process, hydration products can grow on the surface of GO and GO interspersed in the matrix playing the role of riveting, filled the internal holes and cracks of mortar. In the indirect method, GO was used as the film coating onto the surface of the polyethylene fiber (PE). The flexural strength of mortar with GO-C and GO-N coated fiber is increased by 17.24 % and 13.79 %, respectively. While GO-C, GO-N and PE samples increased by 12.07 %, 8.62 % and 10.35 %. GO coated is stronger than the samples using plain PE fiber and GO alone. The SEM indicated that the roughness of fibers was modified by the wrinkled GO surface and GO film modified the bond between fiber and matrix. Molecular dynamics simulation (MD) was employed to analyze the interfacial adsorption characteristics. MD results showed that the interaction between GO-C/C-S-H is 3.03 times of GO-N/C-S-H, GO-C can help matrix to bear more load and GO-C has a higher enhancement than that of GO-N. Anyhow, increasing the bonding and reaction of GO/matrix is crucial to the development of cement-based materials, and efficiently functionalized GO is the focus of future development.

Assessment of the Impacts of Green Synthesized Silver Nanoparticles on Maerua oblongifolia Shoots under In Vitro Salt Stress.

Salinity is one of the major abiotic stresses that affect the plant’s growth and development. Recently, the contribution of nanoparticles (NPs) to ameliorating salinity stresses has become the new field of interest for scientists due to their special physiochemical properties in the biological system. This study is designed to examine the effects of biosynthesized silver nanoparticles (AgNPs) spherical in shape (size range between 9 and 30 nm) on morphophysiological characteristics and the antioxidant defense system of in vitro raised Maerua oblongifolia under four levels of salt stress (0, 50, 100, and 200 mM NaCl). Our findings reveal that the application of AgNPs (0, 10, 20, and 30 mg/L) to M. oblongifolia shoots significantly alleviates the adverse effects of salt stress and ameliorates plant developmental-related parameters and defense systems. High salinity elevates the oxidative damage by over-accumulation of the levels of total soluble sugars, proline, hydrogen peroxide (H2O2), and malondialdehyde (MDA). In addition, enhancing the activity of the antioxidant enzymes, total phenolic, and flavonoid content over the control. Interestingly, the application of AgNPs to salinized plants improved the growth traits and photosynthetic pigment production and caused higher enhancement in antioxidant enzyme activities. Furthermore, mitigating the oxidative damage by lowering the accumulation of proline, soluble sugars, H2O2, MDA, and total phenolic and flavonoid contents in salt-stressed plants. In general, AgNPs augmented the growth of M. oblongifolia shoots under saline conditions through different strategies; thus, AgNPs can be used as an appropriate eco-friendly approach that enhances salinity tolerance in plants.

Application of dynamic contrast enhanced ultrasound in distinguishing focal-type autoimmune pancreatitis from pancreatic ductal adenocarcinoma.

To explore the value of dynamic contrast enhanced ultrasound (DCE-US) in preoperative differential diagnosis of focal-type autoimmune pancreatitis (AIP) and pancreatic ductal adenocarcinoma (PDAC). From May 2016 to March 2020, patients with biopsy and histopathologically confirmed focal-type AIP (n = 9) were retrospectively included. All patients received contrast enhanced ultrasound (CEUS) examinations one week before surgery/biopsy. Dynamic analysis was performed by VueBox® software (Bracco, Italy). Eighteen cases of resection and histopathologically proved PDAC lesions were also included as control group. B mode ultrasound (BMUS) features, CEUS enhancement patterns, time intensity curves (TICs) and CEUS quantitative parameters were obtained and compared between AIP and PDAC lesions. After injection of ultrasound contrast agents, most focal-type AIP lesions displayed hyper-enhancement (2/9, 22.2%) or iso-enhancement (6/9, 66.7%) during arterial phase of CEUS, while most of PDAC lesions showed hypo-enhancement (88.9%) (P < 0.01). During late phase, most of AIP lesions showed iso-enhancement (8/9, 88.9%), while most of PDAC lesions showed hypo-enhancement (94.4%) (P < 0.001). Compared with PDAC lesions, TICs of AIP lesions showed delayed and higher enhancement. Among all CEUS perfusion parameters, ratio of PE (peak enhancement), WiAUC (wash-in area under the curve), WiR (wash-in rate), WiPI (wash-in perfusion index, WiPI = WiAUC/ rise time), WoAUC (wash-out area under the curve), WiWoAUC (wash-in and wash-out area under the curve) and WoR (wash-out rate) between pancreatic lesion and surrounding normal pancreatic tissue were significantly higher in AIP lesions than PDAC lesions (P < 0.05). DCE-US with quantitative analysis has the potential to make preoperative differential diagnosis between focal-type AIP and PDAC non-invasively.

The synergistic effect of hybridizing and aligning graphene oxide nanoplatelets and multi-walled carbon nanotubes on mode-I fracture behavior of nanocomposite adhesive joints

The synergistic effect of hybridizing and aligning graphene oxide nanoplatelet (GONP) and multi-walled carbon nanotube (MWCNT) on the mode-I fracture response of glass fiber/epoxy nanocomposite adhesive was studied. Different mixtures of nanofillers with aligned and random orientations and different mixing ratios and weight percentages were used for fabricating the reinforced nanocomposite adhesive joints. The results showed that the hybridization of MWCNTs and GONPs can considerably enhance the fracture behavior of nanocomposite adhesive joints providing that the appropriate hybrid ratio and weight percentage (wt%) were employed. It was found out that hybridizing one-third GONPs and two-thirds MWCNTs with 0.3 total nanofiller wt% caused 90% further improvement in the fracture energy of adhesive compared to the adhesive reinforced with merely MWCNTs at the same total nanofiller wt%. Furthermore, aligning nanofillers with electrical field resulted in more than twice the higher enhancement in the fracture energy of adhesive. Moreover, assessing the fracture surfaces of the unreinforced and reinforced specimens revealed that the type of reinforcement can affect the failure pattern of the adhesive joints.

Heat transfer, pressure drop, and exergy analyses of a shot-peened tube in the tube heat exchanger using Al2O3 nanofluids for solar thermal applications

The effects of shot peening on the heat transfer, exergy analysis, and pressure drop in the heat exchanger were studied. Nanofluids were produced at different volume concentrations of 0.15, 0.3, and 0.45% of alumina oxide (Al2O3) nanomaterials well dispersed in solar glycol/water (80:20 by volume) as a base fluid. The outcomes point out that nanofluids (0.15, 0.3, and 0.45%) can enhance the Nusselt number by 8.098, 16.81, and 26.98%, compared with SG/H2O mixture respectively when compared with the SG-H2O blend with an impelling penalty of 1.47 folds. A higher enhancement in the CHTC of 56.32% was attained using 0.45 vol% of Al2O3 nanofluids at 0.08 kg/s. TEF of 1.118 is attained for the 0.45 vol% nanofluid inside the surface-modified (shot peening) heat exchanger. The maximal exergy efficiency was found to be 30.82% for 0.45 vol% of SG-H2O-based nanofluids and nanofluid MFR of 0.08 kg/s.

Magnetic resonance imaging indicators for neurological outcome after surgery in patients with intramedullary spinal ependymomas.

This is a retrospective study. The aim of this study was to determine the indicators of neurological outcome after surgery in patients with intramedullary spinal ependymomas by using magnetic resonance imaging (MRI).A total of 106 consecutive patients (mean age: 42.4 ± 1.3 years; 52.8% male) diagnosed with intramedullary spinal ependymomas were retrospectively recruited. All patients underwent spine MRI and subsequent surgical resection for the spinal tumors. Data regarding clinical symptoms and pathological grades of tumors were collected from clinical records. The McCormick score was used for grading patients’ neurological status before and after surgery at 12 months. Good outcome was defined as stable McCormick score (McC) score (no change of McC score between preoperation and post-operation at 12 months) or improvement in McC score (post-operative McC score at 12 months < preoperative McC score). Poor outcome was determined when there was an increase in McC score at 12 months after surgery. The MRI characteristics of spinal ependymomas between patients with good and poor neurological outcomes were compared. Logistic regression was performed to assess the association between MRI characteristics of tumors and post-operative neurological outcomes.Patients with poor neurological outcomes had larger longitudinal length (4.7 ± 0.5 vs 3.3 ± 0.2, P = .004) and higher enhancement signal-to-noise-ratio (SNR) (102.4 ± 12.3 vs 72.8 ± 4.6, P = .022) than those with good neurological outcomes. After adjusting for confounding factors, longitudinal length (OR, 0.768; 95% CI, 0.604–0.976; P = .031) and enhancement SNR (OR, 0.988; 95% CI, 0.978–0.999; P = .026) of spinal ependymomas were significantly associated with poor neurological prognosis.The longitudinal length of tumor and enhancement SNR on T1-weighted images are independently associated with neurological outcome after surgery.

Limits in enhancement factor in near-brewster angle reflection pump-probe two-dimensional infrared spectroscopy

In this work, we simulated 2D infrared spectroscopy (IR) spectroscopy in both transmission geometry and Brewster-angle reflection geometry. Light dispersion and the leakage of s-polarized light are considered in simulating the enhancement factor of the reflection mode. Our simulation shows that the dispersion in reflection will only alter the 2D IR lineshape slightly and can be corrected. Leaking spolarized light due to imperfectness of IR polarizers in the reflection geometry may limit the enhancement factor, but such limit is above what a typical experiment can reach. In the current experiment, the enhancement factor is mainly limited by the precision of incident angle, for which ordinary rotation stages are probably not adequate enough. Moreover, traditional energy ratio of pump and probe pulses, which is 9:1, may not be ideal and could be changed to 2:1 in the reflection geometry. Considering all the above factors, the enhancement on the order of 1000 is possible in the current experiment. Nevertheless, near-Brewster angle reflection will enhance both the signal and the noise caused by the signal itself, therefore this method only works if the noise is unrelated to the signal, particularly if the noise is caused by the fluctuation in the probe. It cannot improve the signal to noise ratio when the dominate noise is from the signal itself. The theoretical results here agree reasonably well with published experiment results and pave way for realizing even higher enhancement at nearer-Brewster angle.