Behavior of Composites Made of Quadriaxial Glass Fiber Fabrics and Epoxy Resin under Three-Point Bending.

This paper presents experimental results from three-point bending tests for a composite made of quadriaxial glass fiber fabrics and an epoxy resin. Two composites were tested, one with 8 layers and the other with 16 layers; both had the same matrix (the epoxy resin). Tests were carried out, using five different test rates from 10 mm/min to 1000 mm/min. The following parameters were recorded and calculated: Young's modulus, flexural stress, flexural strain, energy, force, and all four for the first peak. The experimental data reveal no sensitivity for these materials based on the test rates, at least for the analyzed range; but, the characteristics for the thicker composite, with 16 layers of fabric, are slightly lower than those for the thinner composite, with 8 layers. The results pointed out that, for the same thickness of composite, certain characteristics, such as stress at the first peak, the flexural modulus, strain at the first peak, and energy at the first peak, are not sensitive to the test rate in the range 10-1000 mm/min. The energy at the first peak is double for the 16-layer composite compared to the 8-layer composite, but the specific energy (as energy on cross-sectional area) has close values: 103.47 kJ/m2 for the 8-layer composite and 106.51 kJ/m2 for the 16-layer composite. The results recommend this composite for applications in components with resistance to bending or for low-velocity impact protection.

Cystic Echinococcosis in Hospitalized Adult Patients from Western Romania: 2007-2022.

Cystic echinococcosis (CE) is a neglected parasitic disease caused by the tapeworm Echinococcus granulosus. The aim of this study was to assess the epidemiological features of human cystic echinococcosis in patients from Western Romania. We retrospectively investigated the medical records of patients hospitalized with CE between 1 January 2007 and 1 September 2022. A total of 366 patients (range 18-90 years) were recorded. The number of hospitalized individuals was higher in patients aged 50-59 years (83/366, 22.7%), in females (194/366, 53%), and in residents of rural areas (225/366, 61.5%). The liver was the most common localization of the cysts (302/366, 82.5%). Ninety-eight patients (26.8%) presented complications, including biliary fistula, allergies, and infection of the cyst. Patients with complications had a longer mean hospital stay (15.7 ± 8.3 days) compared to patients without complications (11.5 ± 7.3 days) (p < 0.001). The results of this study revealed that patients diagnosed with CE required hospitalization and extended medical care, indicating that this zoonotic disease remains a significant public health problem in Western Romania. Public health authorities should enhance CE surveillance by implementing control programs and mandatory notification of new cases.

Ballistic Response of a Glass Fiber Composite for Two Levels of Threat.

This paper presents the behavior of composite panels based on glass fiber unidirectional fabrics and a bi-component epoxy resin under ballistic impacts that characterize two threat levels: FB2 and FB3, according to EN 1523:2004. The tested panels had characteristics kept in narrow ranges: thickness 18.26 ± 0.22 mm, mass ratio fabrics/panel 0.788 ± 0.015, surface density 27.51 ± 0.26 kg/m2. After testing the panels, the failure mechanisms of the panel were evidenced by scanning electron microscopy and photographs. Here the authors present a finite-element model at meso scale that was used for evaluating if the composite, initially tested at level FB2 (9 mm FMJ, v0 = 375 m/s), could withstand the higher level of impact, FB3 (projectile type 0.357 Magnum and impact velocity of v0 = 433 m/s). Simulation was performed in Explicit Dynamics (Ansys), keeping the same target but changing the projectile for the two different levels of threat. The results of the simulation were encouraging for making tests at level FB3, indicating the importance of alternating actual tests with simulations in order to achieve better protection with reduced surface weight. The simulation illustrated differences in impact duration and number of layers broken on the panel for each level. Validation of the model was based on the number of broken layers and the dimension of the delamination zone between the last two layers. Scanning electron microscopy was used for identifying failure mechanisms at the micro and meso scale. We found that damage to the composite was intensively dependent on impact velocity, this being quantitatively evaluated using the number of layers broken, the effect of delamination on separating layers and the deformation of the last layer.

The Behavior of Glass Fiber Composites under Low Velocity Impacts.

This paper presents experimental results on the behavior of a class of glass fiber composites under low velocity impacts, in order to analyze their usage in designing low velocity impact-resistant components in car and marine industries. Also, a finite element model at the meso level (considering yarn as a compact, homogenous and isotropic material) was run with the help of Ansys Explicit Dynamics in order to point out the stages of the failure and the equivalent stress distribution on the main yarns in different layers of the composite. The composites were manufactured at laboratory scale via the laying-up and pressing method, using a quadriaxial glass fiber fabric (0°/+45°/90°/-45°) supplied by Castro Composites (Pontevedra, Spain) and an epoxy resin. The resin was a two-component resin (Biresin® CR82 and hardener CH80-2) supplied by Sika Group (Bludenz, Austria). The mass ratio for the fabric and panel was kept in the range of 0.70-0.77. The variables for this research were as follows: the number of layers of glass fiber fabric, the impact velocity (2-4 m/s, corresponding to an impact energy of 11-45 J, respectively) and the diameter of the hemispherical impactor (Φ10 mm and Φ20 mm) made of hardened steel. The tests were performed on an Instron CEAST 9340 test machine, and at least three tests with close results are presented. We investigated the influence of the test parameters on the maximum force (Fmax) measured during impact, the time to Fmax and the duration of impact, tf, all considered when the force is falling to zero again. Scanning electron microscopy and photography were used for discussing the failure processes at the fiber (micro) and panel (macro) level. At a velocity impact of 2 m/s (corresponding to an impact energy of 11 J), even the thinner panels (with two layers of quadriaxial glass fiber fabric, 1.64 mm thickness and a surface density of 3.51 kg/m2) had only partial penetration (damages on the panel face, without damage on panel back), but at a velocity impact of 4 m/s (corresponding to an impact energy of 45 J), only composite panels with six layers of quadriaxial fabric (5.25 mm thickness and a surface density of 9.89 kg/m2) presented back faces with only micro-exfoliated spots of the matrix for tests with both impactors. These results encourage the continuation of research on actual components for car and naval industries subjected to low velocity impacts.

COVID-19 Pandemic Effects on Cervical Cancer Diagnosis and Management: A Population-Based Study in Romania.

The Pap test plays a significant role worldwide in the early diagnosis of and high curability rates for cervical cancer. However, the coronavirus disease 2019 (COVID-19) pandemic necessitated the use of multiple drastic measures to stop the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, limiting women's access to essential invasive and non-invasive investigations for cervical cancer diagnosis. Therefore, we aimed to determine the impact the COVID-19 pandemic had on cancer diagnosis and management in western Romania. A retrospective study design allowed us to compare the last 24 months of the pre-pandemic period with the first 24 months of the COVID-19 pandemic to determine the change in volume of cervical screening tests, the number of newly diagnosed cases and their severity, and the access to cancer care. A drastic 75.5% decrease in the volume of tests was observed in April 2020 during the first lockdown, after which the volume of cases decreased by up to 36.1% in December 2021. The total volume loss of tests during the first 24 months of the pandemic was 49.9%. The percentage of late-stage cervical cancers (III-IV) rose by 17%, while the number of newly diagnosed cancers in our outpatient clinic was significantly lower than the baseline, with a 45% drop. The access to cancer care was negatively influenced, with 9.2% more patients waiting longer to receive test results over four weeks, while taking longer to seek cancer care after diagnosis (6.4 months vs. 4.1 months pre-pandemic) and missing significantly more appointments. The COVID-19 pandemic had a significantly negative impact on cervical cancer diagnosis and management during the first 24 months compared with the same period before the pandemic. Although the numbers are now recovering, there is still a big gap, meaning that many cervical cancer cases were potentially missed. We recommend further interventions to reduce the gap between the pre-pandemic and pandemic period.

COVID-19 Pandemic Impact on Surgical Treatment Methods for Early-Stage Cervical Cancer: A Population-Based Study in Romania.

Being one of the most common malignancies in young women, cervical cancer is frequently successfully screened around the world. Early detection enables for an important number of curative options that allow for more than 90% of patients to survive more than three years without cancer relapse. Unfortunately, the COVID-19 pandemic put tremendous pressure on healthcare systems and access to cancer care, determining us to develop a study on the influence the pandemic had on surgical care of cervical cancer, and to assess changes in its management and outcomes. A retrospective study design allowed us to compare cervical cancer trends of the last 48 months of the pre-pandemic period with the first 24 months during the COVID-19 pandemic, using the database from the Timis County Emergency Clinical Hospital. New cases of cervical cancer presented to our clinic in more advanced stages (34.6% cases of FIGO stage III during the pandemic vs. 22.4% before the pandemic, p-value = 0.047). These patients faced significantly more changes in treatment plans, postponed surgeries, and postponed radio-chemotherapy treatment. From the full cohort of cervical cancer patients, 160 were early stages eligible for curative intervention who completed a three-year follow-up period. The disease-free survival and overall survival were not influenced by the surgical treatment of choice, or by the SARS-CoV-2 infection (log-rank p-value = 0.449, respectively log-rank p-value = 0.608). The individual risk factors identified for the three-year mortality risk were independent of the SARS-CoV-2 infection and treatment changes during the COVID-19 pandemic. We observed significantly fewer cases of cervical cancer diagnosed per year during the first 24 months of the COVID-19 pandemic, blaming the changes in healthcare system regulations that failed to offer the same conditions as before the pandemic. Even though we did not observe significant changes in disease-free survival of early-stage cervical cancers, we expect the excess of cases diagnosed in later stages to have lower survival rates, imposing the healthcare systems to consider different strategies for these patients while the pandemic is still ongoing.

Difficulties in Diagnosing Extraperitoneal Ureteroinguinal Hernias: A Review of the Literature and Clinical Experience of a Rare Encounter in Acute Surgical Care Settings.

Although inguinal hernia repair is one of the most common surgical procedures, finding a retroperitoneal structure, such as the ureter, is a rather rare occurrence. Ureteroinguinal hernias may arise in the presence or absence of obstructive uropathy, the latter raising difficulties in diagnosis for the general surgeon performing a regular inguinal hernia surgery. This study aims to collect the relevant literature describing the diagnosis and management of ureteroinguinal hernias and update it with a case encountered in our clinic. The following study was reported following the SCARE guidelines. The relevant literature describes less than 150 cases of ureteroinguinal hernias overall, considering the 1.7% prevalence of inguinal hernias in the general population. With only 20% of these hernias being described as extraperitoneal, such an encounter becomes an extremely rare finding. Our clinical experience brings a case of a 75-year-old male with frequent urinary tract infections and a large irreducible inguinoscrotal hernia of about 20/12 cm located at the right scrotum. The patient underwent an open inguinal hernia repair technique under general anesthesia, incidentally finding an extraperitoneal ureteral herniation. Segmental ureterectomy was performed with uneventful recovery. Intraoperatively, finding an incidental ureteroinguinal hernia raises concerns about probable urinary tract complications during regular hernia repair surgery and whether the diagnosis is likely to happen prior to surgical intervention. Although imaging is rarely indicated in inguinal hernias, the case reports show that a pelvic CT scan with urography in symptomatic patients with urinary symptoms will provide accurate confirmation of the diagnosis. The relevant literature is limited due to the rarity of respective cases, thus making standardized management of such cases unlikely.

Failure Investigation of Layered LFT SB1plus Package after Ballistic Tests for Level IIA.

The main objective of this study focuses on designing and testing body protection systems using advanced materials based on aramid fibers, for high impact speeds of up to 420 ± 10 m/s. Ballistic applications of aramid fiber-based composites mostly include soft body armors. The investigation of the failure mechanisms identifies issues of protective fabrics, major challenges and technological problems for efficient development of these systems. The authors present an investigation on the failure processes and destructive stages of a ballistic package made of successive layers of LFT SB1plus, a trade name for a multiaxial fabric by Twaron Laminated Fabric Technology (LFT), taking into account the particular test conditions from NIJ Standard-0101.06 Ballistic Resistance of Body Armor. The main parameter of interest was the backface signature (BFS), but also details of projectile arrest and SEM investigation could offer arguments for using this material for individual protection. For the reported tests, the maximum and minimum values for BFS were 12 mm and 24 mm, the mean value being 18.66 mm and the standard deviation being 3.8 mm.

Numerical and Experimental Results on Charpy Tests for Blends Polypropylene + Polyamide + Ethylene Propylene Diene Monomer (PP + PA + EPDM).

This paper presents results from numerical and experimental investigation on Charpy tests in order to point out failure mechanisms and to evaluate new polymeric blends PP + PA6 + EPDM. Charpy tests were done for initial velocity of the impactor of 0.96 m/s and its mass of 3.219 kg and these data were also introduced in the finite element model. The proposed model takes into account the system of four balls, including support and the ring of fixing the three balls and it has a finer discretization of the impact area to highlight the mechanisms of failure and their development in time. The constitutive models for four materials (polypropylene with 1% Kritilen, two blends PP + PA6 + EPDM and a blend PA6 + EPDM) were derived from tensile tests. Running simulations for each constitutive model of material makes possible to differentiate the destruction mechanisms according to the material introduced in the simulation, including the initiation and the development of the crack(s), based on equivalent plastic strain at break (EPS) for each material. The validation of the model and the simulation results were done qualitatively, analyzing the shape of broken surfaces and comparing them to SEM images and quantitatively by comparing the impact duration, energy absorbed by the sample, the value of maximum force during impact. The duration of the destruction of the specimen is longer than the actual one, explainable by the fact that the material model does not take into account the influence of the material deformation speed in Charpy test, the model being designed with the help of tests done at 0.016 m/s (1000 mm/min) (maximum strain rate for the tensile tests). Experimental results are encouraging for recommending the blends 20% PP + 42% PA6 + 28% EPDM and 60% PA6 + 40% EPDM as materials for impact protection at low velocity (1 m/s). Simulation results are closer to the experimental ones for the more brittle tested materials (with less content of PA6 and EPDM) and more distanced for the more ductile materials (with higher content of PA6 and EPDM).