High Density Research Articles

Residual deformation analysis of laser powder bed fusion-fabricated lattice structures

ABSTRACT Lattice structures are crucial for weight reduction, and laser powder bed fusion (LPBF) is an efficient fabrication method. However, there's a notable research gap in understanding the residual deformation of LPBF-fabricated lattice structures. This study investigates the residual deformation of three basic lattice structures, body centre cell (BCC), face centre cell (FCC), and diamond cell (DC), fabricated via LPBF to reveal their deformation mechanisms. Analysis covers horizontal direction, building direction, and total deformations, unveiling complex structural responses. Lower relative densities exhibit a prevalent structural deformation mode (SDM) causing significant deformations, while higher densities shift to an intrinsic deformation mode (IDM) dominated by contraction during fabrication. The FCC structure shows optimal stability with minimal residual deformation across most densities. This study offers insightful findings and a detailed mechanistic analysis of residual deformation in LPBF-fabricated lattice structures, applicable across various configurations, ensuring design process uniformity and reliability.

Sex differences in the distribution and density of regulatory interneurons in the striatum

IntroductionDysfunction of the cortico-basal circuitry – including its primary input nucleus, the striatum – contributes to neuropsychiatric disorders, such as autism and Tourette Syndrome (TS). These conditions show marked sex differences, occurring more often in males than in females. Regulatory interneurons, such as cholinergic interneurons (CINs) and parvalbumin-expressing GABAergic fast spiking interneurons (FSIs), are implicated in human neuropsychiatric disorders such as TS, and ablation of these interneurons produces relevant behavioral pathology in male mice, but not in females. Here we investigate sex differences in the density and distribution of striatal interneurons.MethodsWe use stereological quantification of CINs, FSIs, and somatostatin-expressing (SOM) GABAergic interneurons in the dorsal striatum (caudate-putamen) and the ventral striatum (nucleus accumbens) in male and female mice.ResultsMales have a higher density of CINs than females, especially in the dorsal striatum; females have equal distribution between dorsal and ventral striatum. FSIs showed similar distributions, with a greater dorsal-ventral density gradient in males than in females. SOM interneurons were denser in the ventral than in the dorsal striatum, with no sex differences.DiscussionThese sex differences in the density and distribution of FSIs and CINs may contribute to sex differences in basal ganglia function, particularly in the context of psychopathology.

Combined conventional factors and the radiomics signature of coronary plaque texture could improve cardiac risk prediction

ObjectivesThis study aims to investigate how radiomics analysis can help understand the association between plaque texture, epicardial adipose tissue (EAT), and cardiovascular risk. Working with a Photon-counting CT, which exhibits enhanced feature stability, offers the potential to advance radiomics analysis and enable its integration into clinical routines.MethodsCoronary plaques were manually segmented in this retrospective, single-centre study and radiomic features were extracted using pyradiomics. The study population was divided into groups according to the presence of high-risk plaques (HRP), plaques with at least 50% stenosis, plaques with at least 70% stenosis, or triple-vessel disease. A combined group with patients exhibiting at least one of these risk factors was formed. Random forest feature selection identified differentiating features for the groups. EAT thickness and density were measured and compared with feature selection results.ResultsA total number of 306 plaques from 61 patients (mean age 61 years +/− 8.85 [standard deviation], 13 female) were analysed. Plaques of patients with HRP features or relevant stenosis demonstrated a higher presence of texture heterogeneity through various radiomics features compared to patients with only an intermediate stenosis degree. While EAT thickness did not significantly differ, affected patients showed significantly higher mean densities in the 50%, HRP, and combined groups, and insignificantly higher densities in the 70% and triple-vessel groups.ConclusionThe combination of a higher EAT density and a more heterogeneous plaque texture might offer an additional tool in identifying patients with an elevated risk of cardiovascular events.Clinical relevance statementCardiovascular disease is the leading cause of mortality globally. Plaque composition and changes in the EAT are connected to cardiac risk. A better understanding of the interrelation of these risk indicators can lead to improved cardiac risk prediction.Key PointsCardiac plaque composition and changes in the EAT are connected to cardiac risk.Higher EAT density and more heterogeneous plaque texture are related to traditional risk indicators.Radiomics texture analysis conducted on PCCT scans can help identify patients with elevated cardiac risk.Graphical

Enhancing mode-II delamination resistance of hybrid woven composite materials of glass/Kevlar fabrics by stitching with Kevlar threads

This study analyzes the effects of stitching a hybrid composite beam on its Mode-II delamination to enhance the bonding between a Kevlar-Kevlar interface. The material under investigation is a composite material manufactured from fiberglass and Kevlar fabrics stitched together with Kevlar threads before the infusion of epoxy resin. End-notched flexure tests and multiscale finite element simulations are conducted to validate a glass/epoxy composite with a glass-glass interface. Calibrated simulations are then used to perform a parametric study on stitching parameters, including stitch spacing, pitch, and direction on a composite with a Kevlar-Kevlar interface. The parametric study on Kevlar-Kevlar specimens revealed an average improvement of 17 % in maximum load capacity and 103 % in tangent stiffness in stitched specimens compared to unstitched specimens. Additionally, increasing stitch density up to 0.02 mm−2 significantly enhances mechanical performance, while higher densities do not provide significant additional improvements.

A comparative approach for life history and functional response demonstrates similar survival strategies for Trichogramma evanescens and T. pintoi.

Egg parasitoids are important biological control agents of lepidopteran pests of agricultural crops. Trichogramma evanescens Westwood and T. pintoi Voegele (Hymenoptera: Trichogrammatidae) are egg parasitoids with worldwide importance. The parasitoid selection necessitates comparative assessment of the life table traits and functional response analysis to provide insights into their effectiveness in pest control. In this study, we examined theirlife table traits including survivorship and reproductivity, and functional response and associated parameters i.e., attack coefficient and handling time. Life table parameters, using age-stage, two-sex theory, revealed similar survival and reproductive strategies for both species. For example, the female longevity, oviposition days and fecundity did not differ between both species. Exceptionally, the male longevity of T. evanescens was shorter than that of T. pintoi. The population growth parameters such as gross reproductive rate (GRR), net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ), and mean generation time (T) did not differ between species. The polynomial logistic regression yielded a type III functional response and a non-linear least square analysis revealed different attack coefficient and similar handling time. However, their parasitism rate differed between the lowest (five eggs) and highest (80 eggs) initial host egg densities such that T. evanescens had a lower parasitism rate at the lowest density and higher parasitism rate at the highest density. The similarity in survival strategies and minor differences in host handling of both parasitoids are discussed in terms of relevance to applied biological control applications and evolutionary traits. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Association between high-density mapping of atypical atrial flutter, clinical outcomes and healthcare utilization.

Success of atypical atrial flutter (AAFL) ablation has historically been limited by difficulty mapping the complex re-entrant circuits involved. While high-density (HD) mapping has become commonplace in clinical practice, there are limited data on outcomes of HD versus non-HD mapping for AAFL ablation. To compare clinical outcomes and healthcare utilization using HD mapping versus non-HD mapping for AAFL ablation. Retrospective analysis of all AAFL procedures between 2005 and 2022 at an academic medical center was conducted. Procedures utilizing a 16-electrode HD Grid catheter and Precision mapping system were compared to procedures using prior generation 10-20 electrode spiral catheters and the Velocity system (Abbott, IL). Cox regression models and Poisson regression models were utilized to examine procedural and healthcare utilization outcomes. Models were adjusted for left ventricular ejection fraction, CHA2DS2-VASc, and history of prior ablation. There were 108 patients (62% HD mapping) included in the analysis. Baseline clinical characteristics were similar between groups. Use of HD mapping was associated with a higher rate of AAFL circuit delineation (92.5% vs. 76%; p = .014) and a greater adjusted procedure success rate, defined as non-inducibility at procedure end, (aRR (95% CI) 1.26 (1.02-1.55) p = .035) than non-HD mapping. HD mapping was also associated with a lower rate of ED visits (aIRR (95% CI) 0.32 (0.14-0.71); p = .007) and hospitalizations (aIRR (95% CI) 0.32 (0.14-0.68); p = .004) for AF/AFL/HF through 1 year. While there was a lower rate of recurrent AFL through 1 year among HD mapping cases (aHR (95% CI) 0.60 (0.31-1.16) p = .13), statistical significance was not met likely due to the low sample size and higher rate of ambulatory rhythm monitoring in the HD group (61% vs. 39%, p = .025). Compared to non-HD mapping, AAFL ablation with HD mapping is associated with improvements in the ability to define the AAFL circuit, greater procedural success, and a reduction in the number of ED visits and hospitalization for AF/AFL/HF.

O-196 Men who fathered embryos with poor pre-implantation development rates exhibit an increased frequency of sperm with high DNA accessibility

Abstract Study question Do differing levels of DNA accessibility in sperm affect the ability of embryos generated by ART to undergo pre-implantation development? Summary answer Individuals whose sperm generated embryos that failed to efficiently form blastocysts tend to have more sperm with high levels of DNA accessibility. What is known already Chromatin is a complex composed of nucleic acids and proteins that serves to condense and regulate the genome in all eukaryotic cells. Sperm chromatin is packaged into a structure with higher density than that found in precursor germ cells or somatic cells. Samples from individuals with decreased normal semen parameters have previously been shown to possess an increased frequency of sperm with aberrant chromatin packaging. However, existing methodologies for measuring sperm chromatin packaging are indirect and non-quantitative. Study design, size, duration Prospective cohort study, registered January 2020. We adapted an enzymatic methodology for measuring DNA accessibility known as NicE-view (Nicking Endonuclease-mediated visualization), for use in human sperm. DNA accessibility was quantified in three millions of individual sperm from semen obtained from 60 individuals. Both total sperm and sperm selected for motility via swim-up were analyzed for each participant. Participants/materials, setting, methods Participants sought treatment for infertility at Universitätsspital Basel and possessed normospermic levels in conventional semen analysis. Participant partners had normal endocrine parameters and ovulation response to hormonal stimulation. 20 couples obtained pregnancies without the need for ART, while 40 individuals who were treated using ART and divided into two groups differing in pre-implantation development rates: (1) 20 with blastocyst development of > 50% of all zygotes and (2) 20 produced 0-1 blastocyst following embryo culture. Main results and the role of chance We quantified DNA accessibility and the presence of single stranded DNA nicks in more than 3 million sperm derived from 117 samples. We found that while DNA nicks were only present in a small fraction of the sperm analyzed, DNA accessibility levels varied dramatically with the data indicating a bimodal distribution. At a single sperm level, DNA accessibility and the presence of single stranded DNA damage both correlated with nuclear size. We found that DNA nicking was more abundant in total sperm samples compared to sperm selected for motility via swim-up preparation. In contrast, sperm with high levels of DNA accessibility were more abundant following swim-up, perhaps resulting from capacitation. We observed that individuals with a history of low blastocyst development were more likely to have high frequencies of sperm harboring DNA nicks and high DNA accessibility. We also measured increased frequencies of sperm with high DNA accessibility to negatively correlate with conventional semen parameter values. Limitations, reasons for caution Our study cohort consists of only 60 individuals. Variation is also observed between individuals within each participant category, so further analysis with increased participant numbers is required to strengthen these conclusions. Wider implications of the findings Our results suggest measuring DNA accessibility in sperm from normospermic individuals provide additional information about the efficiency of pre-implantation development following ART. Future work examining the sources of increased DNA accessibility in sperm will also be interesting to identify possible treatments for such individuals. Trial registration number SNCTP000003654 | NCT04256668

Mechanical Properties of Underutilized Hardwood Species and Potential for Use in Fabrication of Cross-Laminated Timber Industrial Mats

Abstract This research evaluated the mechanical and physical properties of three underutilized hardwood species according to visual lumber grades. Findings are discussed in relation to the requirements recommended such as density, modulus of rupture (MOR), and modulus of elasticity (MOE) for the manufacture of cross-laminated timber (CLT) industrial mats, which is a potential end use of low-valued hardwood species. Results showed that all species tested had an average MOE greater than that required for CLT lumber. Visual grading was an important component in strength determinations as evidenced by the correlation between MOE and MOR. All grades of red oak (Quercus rubra L.) had higher densities than those of southern yellow pine, which is the traditional wood used in manufacturing CLT industrial mats, with a density of 616 kg/m3 at 12 percent moisture; the average density of the red oak tested was 770 kg/m3 at 13.98 percent moisture. All grades of red oak also had MOE and MOR values that met the requirements for lumber used in the manufacture of CLT industrial mats. For sweetgum (Liquidambar styraciflua L.), all grades met the required values for MOE and MOR, but only Grades 3 and 4 met the required density. All grades of yellow poplar (Liriodendron tulipifera L.) met the required MOE and MOR, but none met the required density.

The Effects of Liquid Density and Impeller Size with Volute Clearance on the Performance of Radial Blade Centrifugal Pumps: An Experimental Approach

This study was carried out to experimentally investigate the effect of impeller size with volute clearance and liquid density on the performance of radial blade centrifugal pumps. Three impeller sizes of 121.54mm, 109.38mm and 97.23mm with respective volute clearance of 6mm, 12mm and 18mm were considered, and five different liquid blend which comprise of water, two liquids that are denser than water and two other liquids that are less-dense than water (with respective liquid densities of: 1197 kg/m3 , 1097 kg/m3 , 1000kg/m3 , 898.2 kg/m3 and 798.4 kg/m3 ). In the experimental set-up, the pump flow capacity were varied from 12m3 /hr to 62m3 /hr at interval of 5m3 /hr and the corresponding pump power consumption, attained pump head were recorded and pump efficiency were determined. Microsoft excel was used to evaluate the trend, performance trend was used to develop the pump performance model showing the relationship between the various parameters. The results from the investigation revealed that with the various impeller sizes of 121.54mm, 109.38mm and 97.23mm of respective volute clearance of 6mm, 12mm and 18mm, the attained optimum efficiency were 74.42%, 54.78 and 33.54% respectively at a correspondence optimum pump head of 23.66m, 20.60m and 18.87m. The results also showed that there is a direct relationship between pump power consumption and process liquid density, while showing an inverse linear relationship between the pump instantaneous start up power and impeller diameter. It was therefore concluded among others that liquid with higher density will usually require higher power to initiate and maintain flow at constant flow rate and impeller size. It is then recommended among others that pump designers, application engineers and users of centrifugal pumps should consider possible increase in pump power consumption when working with a process application that has higher tendency for dynamic increase on the process fluid density.

Urinary soluble PD-1 as a biomarker of Checkpoint Inhibitor induced acute tubulointerstitial nephritis

Abstract Background Acute interstitial nephritis (AIN) related to Immune Checkpoint Inhibitors (ICI-AIN) has a not completely understood pathophysiology. Our objectives were to analyze possible biomarkers for the differentiation between acute tubular necrosis (ATN) and AIN, especially in cancer patients, and to study the participation of the immune checkpoint pathway in ICI-AIN. Methods We performed an observational study. We recruited patients with incident diagnosis of ICI-AIN (n=19). We measured soluble PD-1 (sPD-1), sPD-L1 and sPD-L2 in serum and urine at diagnosis and compared to patients with non ICI-related AIN (non-ICI AIN) (n=18) and ATN (n=21). The findings were validated in an independent cohort from another institution (n=30). Besides, we performed PD-L1 and PD-L2 immunostaining of kidney biopsies from patients with ICI-AIN and compared to patients with non-ICI AIN. Results Urinary sPD-1 (usPD-1) was higher in patients with AIN compared to ATN (p=0.03). Patients with AIN also showed higher serum sPD-1 (ssPD-1) than patients with ATN (p=0.021). In cancer patients, usPD-1 <129.3 pg/ml had a 71.43% sensitivity and 94.44% specificity to differentiate ATN from ICI-AIN, with a likelihood ratio of 12.86. In the external validation cohort, the same cutoff showed a sensitivity of 80%. In kidney biopsies, patients with ICI-AIN showed higher density of PD-L1 positive tubules than patients with non-ICI AIN (p=0.02). The proportion of patients having more than 2.64/mm2 PD-L2 positive tubules was higher among patients with ICI-AIN compared to non-ICI AIN (p=0.034). There was a positive correlation (p=0.009, r=0.72) between usPD-1 and the number of PD-L1 positive tubules. Conclusions UsPD-1 and ssPD-1 are higher in AIN than ATN. Moreover, there was a strong correlation between usPD-1 and renal tubular PD-L1 expression. Our findings suggest a role of usPD-1 as non-invasive biomarker to differentiate ICI-AIN from ATN, especially in cancer patients, which has been confirmed in an external validation cohort.

Effectiveness of using hydrophobic silica aerogel and grape seed extract in creating a sunscreen formula

Abstract Wearing sunscreen products protects human skin from the damaging effects of ultraviolet radiation from the sun. An experimental study was conducted to evaluate the effectiveness of utilizing hydrophobic silica aerogel and grape seed extract as additional raw materials in creating a sunscreen formula. This study aims to evaluate the acceptability of the sunscreen formulation in terms of determining its sun protection factor using UV-vis spectrophotometry, ability to remain on the surface using water resistance testing, and shelf life using a stability chamber. The methodology begins with obtaining a modified hydrophobic silica aerogel classified as cosmetic grade. The sunscreen formulation has a combination of 2 wt. % of hydrophobic silica aerogel, 3 wt.% of grape seed oil, and other ingredients using thermal procedures. The results demonstrated that the addition of hydrophobic silica aerogel and grape seed extract in sunscreen formulation exhibits satisfactory UV protection attaining an SPF value of 28.17073 which indicates a medium sun protection factor according to the standardized category of SPF values. On the contrary, the sunscreen without the active ingredients has an SPF value of 4.762. Additionally, both sunscreen’s water resistance was assessed by testing a total of 60 minutes in both tap water and salt water. The findings showed that both samples of sunscreens in tap water were more resistant compared to saltwater. Furthermore, the sunscreen with hydrophobic silica aerogel and grape seed extract stayed intact and did not dissolve in tap water after a 40-minute exposure time, but it did gradually disintegrate after 20 minutes in salt water since salt water has a higher density than tap water. In stability testing of both sunscreen formulations, the results revealed that the moisture content of the sunscreen formulation with hydrophobic silica aerogel and grape seed extract does not exceed 10% which indicates a low presence of oil. Hence, it proves its stability under the controlled conditions of 40°C and 75% relative humidity examined over one (1) month since it had a high moisture content of 78.98% obtained using the gravimetric method. For the sunscreen without these ingredients, the total moisture content under the same conditions and method is 29.07%. Thus, it indicates a high presence of oil and does not attain the standard moisture content for sunscreens. Overall, the evaluated performance of adding the hydrophobic silica aerogel and grape seed extract to the sunscreen formulation ensures its efficacy regarding its SPF, water resistance, and shelf life.

Improved mechanical properties of Al-xMg-yZn-Cu alloys via optimized Mg/Zn ratio and thermomechanical processing

Three Al-xMg-yZn-1Cu alloys with equal total alloying element contents but different Mg/Zn ratios have been prepared in this work, i.e., Al-6Mg-1Zn-1Cu, Al-5Mg-2Zn-1Cu and Al-4Mg-3Zn-1Cu alloys. The influences of Mg/Zn ratios on microstructure and mechanical properties of heat-treated Al-xMg-yZn-1Cu alloys have been systematically studied. The results show that Al-xMg-yZn-1Cu alloys with higher Zn contents exhibit the faster aging response as Zn atom features the largest diffusion coefficient. Additionally, rod shaped and ellipsoidal T´ precipitates are observed in the Al-6Mg-1Zn-1Cu alloy. While in Al-4Mg-3Zn-1Cu alloy under TMT-2 process, T´ precipitates mainly exist in an ellipsoidal shape, with a higher number density (∼1.79 × 1023 m-3) and smaller size (∼4.1 nm) compared to the Al-6Mg-1Zn-1Cu alloy. The optimized thermomechanical treatment (80 °C/5 h + rolling + 130 °C/x h) could effectively improve the yield strength of Al-5Mg-2Zn-1Cu and Al-4Mg-3Zn-1Cu alloys, with values increasing from ∼419 MPa and ∼441 MPa to ∼454 MPa and ∼470 MPa, respectively. In contrast, the Al-6Mg-1Zn-1Cu alloy exhibit almost no increment in yield strength after the same thermomechanical treatment. This could mainly be attributed to the higher density of T´ precipitates in alloys with higher Zn contents, resulting from the higher nucleation rate of T´ precipitates caused by high contents of Zn atoms featuring fast diffusion rates, with the assistance of dislocations introduced by rolling. This work provides theoretical supports for the development and production of age-hardenable Al-xMg-yZn-1Cu alloys.

Pulsed TIG wire arc additive manufactured 17-4PH stainless steel: Effect of Cu-rich precipitates and δ-ferrite on the mechanical properties

Thin-wall samples of 17-4PH stainless steel were prepared by pulsed TIG wire arc additive manufacturing technology (P-TIG WAAM), and the microstructure and mechanical properties of the samples in different regions (bottom, middle, top) were studied. The results show that the microstructure of the thin-wall samples are mainly consisted of martensite matrix embedded by worm-like (bottom) and strip-shaped (top) δ-ferrite, with a small amount of austenite. The δ-ferrite content gradually decreases along the building direction, resulting in a gradual increase in microhardness from the bottom to the top. Along the building direction, the precipitation density and size distribution of nano-scale CRPs (Cu-rich precipitates) in δ-ferrite and martensite, as well as at the δ-ferrite / martensite interface are significantly different: the CRPs in δ-ferrite is precipitated with lower density, larger size, and inhomogeneous distribution at the bottom region, while that in martensite is precipitated with higher density, smaller size, and homogeneous distribution. At the bottom region, a chain of large size fcc-CRPs (∼65 nm) is precipitated along the δ-ferrite / martensite interface to coordinate the strain between them and improve the strength and ductility simultaneously, thus excellent mechanical properties (tensile strength = 1356±24 MPa, elongation =15.16±2.6%) are obtained. The relationship between the evolution of CRPs and the intrinsic heat treatment (IHT) during P-TIG WAAM is also discussed.

Molecular dynamics study on hydration characteristics of expansive clay minerals by temperature and inorganic salts

Most strata rock minerals have hydrophilic characteristics and the mineral surface is negatively charged. It can adsorb water molecules to form hydration layers on the mineral surface. The existence of hydration layer will reduce the effective pore diameter of rock pore microchannel. Thus, the development efficiency of crude oil is affected. Hydration layer compared to free water, water molecules are arranged in a highly ordered manner, with higher density and more stable toughness. Therefore, it is very important to study the structure of hydration layer adsorbed on rock wall and its influencing factors. Four different rock and mineral types are selected in this paper: Na-montmorillonite, quartz, kaolinite, calcite. Molecular dynamics method was used to simulate different temperature conditions and adding different inorganic salts. Study the influence of temperature and inorganic salts on the hydration layer structure of rock wall. The simulation results show that the increase of temperature and the addition of inorganic salts of different components have a great influence on the adsorption of water molecules on the rock wall, and it changes the original structure of the hydration layer. The adsorption of water molecules on different rock surfaces and the effect of different rock walls on the adsorption of hydration layer are described in molecular form. This study explains the mechanism of temperature and inorganic salts inhibiting water molecules from a microscopic perspective. It is of great significance to study the physical properties of hydration layer. It provides a theoretical basis for the field well wall stability research.

Effects of the filter media pack configurations on the air filtration performance

Abstract High efficiency particulate air (HEPA) filters are widely used in various industries to contain airborne contamination. The pressure drop of the filters is a crucial performance parameter when designing a HEPA filter as it is the resistance that the filter offers to the flow of air. Thus, it is critical to find the effect of each configuration and integrate an optimal setup for the filter to avoid high-pressure drops. Set against these backgrounds, this study aims to study the effect of different configurations on the total pressure drop of the filter, and to review how each configuration can affect each other using a commercial software ANSYS Fluent. The different filter media pack configurations and boundary conditions investigated here are including pleat shape (V-shaped and U-shaped), pleat density (1-7 pleat/cm), pleat height (1cm, 1.3cm), and inlet velocity (0.02-0.2 m/s) on the pressure drop of the filter. A two-dimensional geometrical model is developed, and then validated with respect to the data obtained from Lydall M3004-06 property sheet. Upon successful validation exercise, a series of parametric studies is conducted to numerically examine the impact of changing each configuration on the total pressure drop of the filter. Results show that an optimal pleat density is attained where the total pressure drop is minimized, i.e., 3 pleat/cm for V-shaped and 4 pleat/cm for U-shaped for inlet velocity of 0.02 m/s. At a constant inlet velocity, the U-shaped pleat has a lower pressure drop than the V-shaped pleat at low pleat densities, but a higher pressure drop at higher densities. This behaviour can be attributed to the balance between inertial and viscous resistance. Increasing the inlet velocity increases the total pressure drop for all pleat heights and decreases the optimal pleat density. This effect is less pronounced on the V-shaped pleat. Increasing the pleat height for the U-shaped pleat decreases the pressure drop and optimal pleat density but increases pressure drop in the viscous dominated region. Conversely, increasing the pleat height for the V-shaped pleat decreases the pressure drop for all pleat counts and only decreases the optimal pleat density at high velocity.

The quiescent population at 0.5 ≤ z ≤ 0.9: Environmental impact on the mass–size relation

Context. How the quiescent galaxies evolve with redshift and the factors that impact their evolution are still debated. It is still unclear what the dominant mechanisms of passive galaxy growth are and what role is played by the environment in shaping their evolutionary paths over cosmic time. Aims. The population of quiescent galaxies is altered over time by several processes that can affect their mean properties. Our aim is to study the mass–size relation (MSR) of the quiescent population and to understand how the environment shapes the MSR at intermediate redshift. Methods. We used the VIMOS Public Extragalactic Redshift Survey (VIPERS), a large spectroscopic survey of ∼90 000 galaxies in the redshift range 0.5 ≤ z ≤ 1.2. We selected a mass-complete sample of 4786 passive galaxies based on the NUVrK diagram and refined it using the Dn4000 spectral index to study the MSR of the passive population over 0.5 ≤ z ≤ 0.9. The impact of the environment on the MSR and on the growth of the quiescent population is studied through the density contrast. Results. The slope and the intercept of the MSR, α = 0.62 ± 0.04 and log(A) = 0.52 ± 0.01, agree well with values from the literature at the same redshift. The intercept decreases with redshift, Re(z) = 8.20 × (1 + z)−1.70, while the slope remains roughly constant, and the same trend is observed in the low-density (LD) and high-density (HD) environments. Thanks to the largest spectroscopic sample at 0.5 ≤ z ≤ 0.9, these results are not prone to redshift uncertainties from photometric measurements. We find that the average size of the quiescent population in the LD and HD environments are identical within 3σ and this result is robust against a change in the definition of the LD and HD environments or a change in the selection of quiescent galaxies. In the LD and HD environments, ∼30 and ∼40% of the population have experienced a minor merger process between 0.5 ≤ z ≤ 0.9. However, minor mergers account only for 30–40% of the size evolution in this redshift range, the remaining evolution likely being due to the progenitor bias.

Jump and hysteresis of plasma density in the spatial afterglow of inductively coupled plasmas

In this work, jump and hysteresis of plasma density between low-density (LD) and high-density (HD) in the spatial afterglow of inductively coupled plasmas are experimentally studied for different gas discharges. A quartz plate with a micropore is used to independently control the pressures in the active plasma and spatial afterglow. The plasma density jump from LD to HD vs the pressure in the spatial afterglow only exists in a larger micropore diameter. By adjusting the pressure back and forth, a hysteresis loop in plasma density is formed. The light intensity and excitation rate vs the pressure corresponds well to the jump and hysteresis of plasma density. Therefore, the abrupt changes in ionization rate are responsible for the jump and hysteresis of plasma density. Compared with argon discharges, the critical pressure for the jump from LD to HD is higher in nitrogen discharges, forming a larger hysteresis loop. For hydrogen discharges, the jump from LD to HD is less significant and the hysteresis loop almost disappears. In argon–hydrogen mixed gas discharges, there is no hysteresis loop in plasma density. Experimental results obtained using Langmuir double probes and spectrometer achieve qualitative agreement in gas discharges mentioned above.

Armature Reaction Analysis and Suppression of Voice Coil Actuator Based on an Improved Magnetic Equivalent Circuit Model

The high thrust density voice coil actuator (VCA) is a key component for the deployers to determine the CubeSats' separation velocity in orbit directly. To improve the VCA's thrust density and power consumption, it is essential to analyze the armature reaction under heavy current work conditions. This paper proposes a dynamic splitting method of the magnetic equivalent circuit (MEC) model for analyzing the armature reaction of the VCA. This MEC model can effectively reveal the interaction mechanism between the dynamic winding field and the permanent magnet (PM) field, which provides an approach to readily and quickly analyze the armature reaction. Based on the understanding of the mechanism, we found an effective way to suppress the armature reaction and propose a new VCA with double PM flux circuits. The electromagnetic performances of the new configuration are evaluated by comparing it with the conventional one. Both the theoretical and experimental results show that the new structure achieves lower magnetic saturation, lower armature reaction, and higher thrust density. A research prototype was constructed and experimentally tested to verify the theoretical results of the armature reaction, magnetic field, thrust, separation velocity, and other performances. The new VCA realizes a wide and accurate modulation of separation velocity for the CubeSats.

A sub-national HIV epidemic appraisal in Kenya: a new approach for identifying priority geographies, populations and programmes for optimizing coverage for HIV prevention.

The HIV Prevention 2025 Roadmap, developed by UNAIDS, recommends the adoption of a precision prevention approach focused on priority populations and geographies. With reduction in new HIV acquisitions in many countries, designing a differentiated HIV prevention response, using a Programme Science approach, based on the understanding of the epidemic and transmission dynamics at a sub-national level, is critical. To support strategic planning, an epidemic appraisal at the sub-national level across 47 counties, with the 2019 population ranging from 0.14 million in Lamu to 4.40 million in Nairobi City, was conducted in Kenya using several existing data sources. Using 2021 Spectrum/EPP/Naomi model estimates of national and sub-national HIV incidence and prevalence, counties with high HIV incidence and prevalence were identified for geographic prioritization. The size of local key population (KP) networks and HIV prevalence in key and general populations were used to define epidemic typology and prioritize populations for HIV prevention programmes. Analysis of routine programme monitoring data for 2021 was used to assess coverage gaps in HIV prevention programmes, including prevention of vertical transmission, anti-retroviral therapy, KP programmes, adolescent girls and young women programme, and voluntary male medical circumcision programme. Ten counties with more than 1000 incident acquisitions in 2021 accounted for 57% of new acquisitions. Twenty-four counties were grouped into the concentrated epidemic type-due to their low prevalence in the general population, high prevalence in KPs and relatively higher density of female sex workers and men who have sex with men populations. Four counties reflected a generalized epidemic, where HIV prevalence was more than 10% and 30%, respectively, among the general and key populations. The remaining 19 counties were classified as having mixed epidemics. Gaps in programmes were identified and counties where these gaps need to be addressed were also prioritized. The HIV burden in Kenya is unevenly distributed and hence the mix of prevention strategies may vary according to the epidemic typology of the county. Prioritization of programmes based not only on disease burden and epidemic typology, but also on the prevailing gaps in coverage for reducing inequities is a key aspect of this appraisal.

Granular sludge characterization and microbial response in a hydroxyapatite (HAP)- anammox coupled process at different nitrogen loading rates

To enhance the treatment capacity and operational stability of the anammox process for nutrient-rich wastewater disposal, a hydroxyapatite (HAP)-anammox coupled process was developed in a granular sludge-based upflow bioreactor. The impact of nitrogen loading rate (NLR) on process performance was investigated by gradually increasing the NLR from 1 to 1.5, 3, and 5 kgN/m3/d for 264 days continuous operation. TN and TP removal rates of 82.51 ± 3.58 % and 60.49 ± 2.82 % were achieved at the NLR of 5 kgN/m3/d. The precipitation of Ca and phosphorus resulted in HAP crystals formation evidenced by sludge morphology and component analysis, which enhanced sludge settling properties and facilitated biomass enrichment. The HAP-anammox granular sludge was characterized by the outer layer HAP crystals formed on inner anammox granules, while highly mineralized granular sludge with higher density distributed at the bottom of the reactor is conducive to HAP-based phosphorus recovery. After a long-term accumulation, the abundance of Planctomycetota phylum gradually increased (from 7.7 % to 14.1 %), consisting of three species of anammox bacteria, namely Candidatus_Brocadia_sapporoensis, Candidatus_Brocadia_sinica and Candidatus_Kuenenia_stuttgartiensis. Nitrogen metabolic pathway analysis illustrated that denitrification was also present except the anammox reaction, synergistically contributing to superior nitrogen removal in the HAP-anammox process.