Preliminary Tests Research Articles

Experimental Study on Chrome Tanned Leather Shavings Modification—Properties and Prospective for Future Application

Chrome tanned leather shavings (CTLS) are considered one of the more difficult wastes to manage in the tanning industry. At the same time, this waste is an important source of good quality collagen. The few methods described in the literature for the valorization of these wastes usually require pre-treatment or activation. In this study, an attempt was made to see if raw chrome tanned leather shavings (CTLS) could be modified to obtain secondary raw materials with new physical properties. Glutaraldehyde, glycerol, EDCs, pectin, and tannins were selected for modification of the CTLS. The effectiveness of the processes carried out was confirmed by FTIR analysis of the materials obtained. Changes in the intensity of the characteristic collagen peak (amide I, amide II, and amide III) and changes in the position of the bands in the 1200–1000 cm−1 region were observed in the recorded spectra. The modifications introduced confirmed changes in the physical properties of samples M1–M5, including an increase in bulk density from 0.15 to 0.59 g cm−3, and improved tensile strength is some cases. The elemental content results of the samples tested showed the resulting modified CTLS were free of Cd, Hg, Pb, and Cr(VI). It was also confirmed tanning waste contained significant amounts of various valuable elements. The research also included preliminary tests to assess the environmental impact of the modified materials. In a phytotoxicity test conducted on modified CTLS, M1 with pectins showed the highest root stimulation (105%), while samples with glutaraldehyde and unmodified CTLS showed significant root inhibition (75%, 74%). Other samples showed moderate plant toxicity and seed germination was not significantly affected.

Selective pseudocapacitive immobilization of REE elements on carbon based electrodes

Current extraction technologies for rare earth elements at ambient conditions are reagent and energy intensive, giving rise to significant quantities of secondary waste streams. Exploration of the removal of common cations from aqueous streams has been undertaken with carbon materials and have shown promising results. However, those promising materials have not been explored extensively for rare earth element capture from aqueous process streams. In this study, a carbon electrode was investigated for the adsorption and immobilization of REE elements from aqueous solutions. Cyclic voltammetry studies of the carbon electrode displayed a pseudocapacitive behavior where it was verified that cation adsorption is accompanied by an electron transfer process. Preliminary tests showed that a current density of 89.1 mA. g−1, allowed for the pseudocapacitive adsorption (PSA) of Nd3+ cation without the formation of rare earth hydroxides. Hence, the selective PSA of Nd3+ was verified in an electrolyte solution with equimolar concentrations of Nd3+, Mg2+, Li+, Na+ and K+, achieving separation factors of 8.6, 1.1, and 10.9 for Nd3+/Li+, Nd3+/Na+, and Nd3+/Mg2+, respectively. Analysis of the potential-time curves for the various cations suggests that storage of ions in the electrode involved pore-spacings rather than interlayer spacings and was corroborated by XRD analysis. Specific capacitance as high as >640 F.g−1 for Nd3+ was also observed for the carbon electrode, with Faradaic efficiencies (FE) of >20 % for Nd3+ and Mg2+, and >9 % for Na+. Furthermore, adsorption capacity of >125 mg g−1 after 4hrs of electrosorption was observed for Nd3+. In the presence of the Nd3+ electrolyte, the electrode achieved increasing storage of Nd3+ with >94 % retention of Nd3+ with a FE > 20 % over 6 cycles between loading and releases in 1 M KCl solution. These preliminary results provide information and some guidance on the selective recovery of rare earth elements, such as Nd, in aqueous streams in the presence of competitive cations employing the use of carbon-based materials.

Phytochemical screening and antioxidant activity of Vitex agnus-castus L.

Abstract This research is dedicated to investigating the antioxidant potential and phytochemical composition of three distinct extracts derived from Vitex agnus-castus L. These extracts, prepared through aqueous (EXA), ethanolic (EXE), and methanolic (EXM) maceration, were chosen based on prior assessments of total polyphenol content in extracts obtained from five solvents with differing polarities: water, methanol, ethanol, acetone, and butanol. The study initiated with a comprehensive phytochemical analysis focusing on the determination of total polyphenols and flavonoids. The quantification of total polyphenols was carried out using the Folin–Ciocalteu method, while the AlCl3 method was employed to assess flavonoids. In evaluating the in vitro antioxidant activity, we employed two well-established methods, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric-reducing antioxidant power (FRAP). The preliminary tests, gauging the efficacy of solvents, demonstrated that the order of optimal solvent selection was as follows: aqueous, methanolic, ethanolic, butanolic, and acetone. Consequently, the first three solvents were chosen for the preparation of the extracts. The phytochemical analysis unveiled that EXA exhibited the highest total polyphenol content, with an impressive value of 126.84 ± 1.24 mg EAG/g extract, whereas EXE exhibited the lowest concentration of total polyphenols, measuring at 117.26 ± 0.18 mg EAG/g extract. In contrast, EXM showcased a notably high flavonoid content, registering at 33.65 ± 1.04 mg EQ/g extract, while EXA displayed a comparatively lower flavonoid content at 14.93 ± 0.14 mg EQ/g extract. When assessing antioxidant properties, EXA emerged as the most potent against both DPPH and FRAP, recording values of 78.94 ± 1.84 and 203.27 ± 0.17 μg/ml, respectively. In contrast, the ethanolic extract exhibited relatively lower antioxidant activity, with values of 204.16 ± 1.87 μg/ml for DPPH and 307.10 ± 1.15 μg/ml for FRAP.

Protocol for evaluation of the feasibility and preliminary efficacy of a targeted transition readiness workshop intervention for pediatric brain tumor survivors

BackgroundPediatric brain tumor survivors (PBTS) are at risk of physical, cognitive, and psychosocial challenges related to their diagnosis and treatment. Routine follow-up care as adults is therefore essential to their long-term health and quality of life. In order to successfully navigate to adult healthcare, it is recommended that youth develop transition readiness skills. Existing transition readiness interventions often focus on disease management. However, PBTS are also at risk of social competence and cognitive functioning challenges. In this paper, we describe the protocol of this pilot study and the methodology that will be used for the evaluation of the feasibility, acceptability, and preliminary efficacy testing of the first targeted transition intervention workshops specifically designed to meet the needs of PBTS and their caregivers.MethodsThis study will use a mixed method to evaluate three 1 ½-h workshops targeted for dyads (N = 40) of PBTS (14 years or older) and their parents. Dyads will be recruited via a community pediatric cancer organization and the long-term follow-up clinic of a large pediatric hospital. Participants will complete an online survey which includes the Transition Readiness Assessment Questionnaire (TRAQ) before and after the workshops.Each workshop will cover a specific topic related to PBTS transition readiness: disease management, social competence, and cognitive functioning. Workshops will follow the same structure: topic presentation, discussion by a post-transfer survivor or parent, teaching two strategies, and workshop evaluation. Workshops will be co-led by healthcare specialists and patient partners.Feasibility and acceptability will be assessed via recruitment, attendance, retention, and Likert scales, and they will be analyzed by describing and comparing rates. Satisfaction will be measured using satisfaction surveys and audio-recorded focus groups. Qualitative data will be described through thematic content analysis. In order to test the preliminary efficacy of this study, we will compare transition readiness skills pre- and post-workshops using paired samples T test and ANCOVA to examine the impact of workshop on TRAQ skills.DiscussionResults of the study will inform refinement and future broader implementation of targeted transition readiness workshops for the specific needs of pediatric brain tumor survivors.

The HealthTracker System: App and Cloud-Based Wearable Multi-Sensor Device for Patients Health Tracking

Telemedicine has emerged as a vital component of contemporary healthcare, revolutionizing the way medical services are delivered and accessed (e.g., it enables patients living in underserved or rural areas to receive medical consultation and treatment remotely). Moreover, telemedicine plays a pivotal role in improving healthcare efficiency by reducing wait times, minimizing unnecessary hospital visits, and optimizing resource allocation. In this paper, we present HealthTracker, a monitoring infrastructure for patients comprising two Internet of Things (IoT) devices (one of which was designed and created by us) and a mobile app that sends data collected by the IoT devices to a cloud service. All these components work together to provide an innovative system able to monitor patient health condition, provide alerts in emergency cases, and elaborate upon data to improve the quality of medical care. Preliminary tests show that the system works well, and real experimentation will start soon in collaboration with the local health authority.

Major stress in early childhood strengthens the association between peripheral inflammatory activity and corticostriatal responsivity to reward

BackgroundSevere, chronic stress during childhood accentuates vulnerability to mental and physical health problems across the lifespan. To explain this phenomenon, the neuroimmune network hypothesis proposes that childhood stressors amplify signaling between peripheral inflammatory cells and developing brain circuits that support processing of rewards and threats. Here, we conducted a preliminary test of the basic premises of this hypothesis. Methods180 adolescents (mean age = 19.1 years; 68.9 % female) with diverse racial and ethnic identities (56.1 % White; 28.3 % Hispanic; 26.1 % Asian) participated. The Childhood Trauma Interview was administered to quantify early adversity. Five inflammatory biomarkers were assayed in antecubital blood — C-reactive protein, tumor necrosis factor-a, and interleukins-6, −8, and −10 — and were averaged to form a composite score. Participants also completed a functional MRI task to measure corticostriatal responsivity to the anticipation and acquisition of monetary rewards. ResultsStress exposure and corticostriatal responsivity interacted statistically to predict the inflammation composite. Among participants who experienced major stressors in the first decade of life, higher inflammatory activity covaried with lower corticostriatal responsivity during acquisition of monetary rewards. This relationship was specific to participants who experienced major stress in early childhood, implying a sensitive period for exposure, and were evident in both the orbitofrontal cortex and the ventral striatum, suggesting the broad involvement of corticostriatal regions. The findings were independent of participants’ age, sex, racial and ethnic identity, family income, and depressive symptoms. ConclusionsCollectively, the results are consistent with hypotheses suggesting that major stress in childhood alters brain-immune signaling.

Measuring tactile sensitivity and mixed-reality-assisted exercise for carpal tunnel syndrome by ultrasound mid-air haptics.

Carpal tunnel syndrome (CTS) is the most common nerve entrapment neuropathy, which causes numbness and pain in the thumb, the index and middle fingers and the radial side of the ring finger. Regular hand exercises may improve the symptoms and prevent carpal tunnel surgery. This study applied a novel ultrasonic stimulation method to test tactile sensitivity in CTS and also a mixed-reality-assisted (MR-assisted) exercise program which measured hand movements and provided haptic feedback for rehabilitation. Twenty patients with mild unilateral CTS took part in the experiments. A mid-air haptics device (Ultrahaptics STRATOS Explore) was used to apply amplitude-modulated ultrasound waves (carrier frequency: 40 kHz) onto the skin to create tactile stimulation mechanically. Participants performed a two-alternative forced-choice task for measuring tactile thresholds at 250-Hz modulation frequency. They were tested at the index fingers and the thenar eminences of both hands. Additionally, 15 CTS patients used an MR-assisted program to do hand exercises with haptic feedback. Exercise performance was assessed by calculating errors between target and actual hand configurations. System Usability Scale (SUS) was adopted to verify the practical usability of the program. Thresholds at the thenar eminences of the affected and healthy hands were not significantly different. While the thresholds at the healthy index fingers could be measured, those of the affected fingers were all higher than the stimulation level produced by the maximum output from the ultrasound device. In the exercise program, a significant positive correlation (ρ = 0.89, p < 0.001) was found between the performance scores and the SUS scores, which were above the criterion value established in the literature. The results show that thenar tactile sensitivity is not affected in mild CTS as expected from the palmar cutaneous branch of the median nerve (PCBm), but index finger threshold is likely to be higher. Overall, this study suggests that mid-air haptics, with certain improvements, may be used as a preliminary test in the clinical setting. Moreover, the device is promising to develop gamified rehabilitation programs and for the treatment follow-up of CTS.

Sensitivity of Preliminary Blood Test on Various Floor Surfaces After Washing with Different Cleansing Products. : Original Work

Blood is important evidence that can assist an investigator in solving a crime. It connects the suspect to a crime and aid in the reconstruction of the crime scene. Criminals frequently attempt to wipe away blood stained evidence at a crime scene. These efforts may result in the modification or partial or total elimination of blood on the stained parts. Numerous presumptive tests are employed to identify bloodstains on floor surfaces since they are frequently cleansed after a crime using various surfactants. However, the traces of stains remain there and if analysed with appropriate reagents will give conclusive results. In This study Blood-stained floor surfaces were cleaned using a commercially available and widely used floor cleaners and After repeated washings, the Kastle-Meyer (KM),Leucomalachite green (LMG), and Tetra methylbenzidine (TMB) tests were employed to determine the presence of blood on these surfaces, and their sensitivity were assessed, this study will help the forensic investigator to select the appropriate reagents for detection of blood stains on the various washed floor surfaces and effectiveness of reagents for detection of blood stains washed with various floor cleaners.

Threshold voltage uniformity improvement by introducing charge injection tuning for low-temperature poly-Si thin film transistors with metal/oxide/nitride/oxide/silicon structure

Low-temperature poly-Si thin film transistors (TFTs) with a metal/oxide/nitride/oxide/silicon structure were fabricated to investigate the feasibility of suppressing threshold voltage variations between TFTs. By applying relatively high positive and negative gate bias voltages, threshold voltage could be tuned positively and negatively, respectively, by injecting charges into the charge trap layer. Stability of threshold voltage against positive gate bias at a level close to the actual circuit operation was not degraded compared with the case of an as-fabricated TFT. A uniform threshold voltage distribution could be achieved in a preliminary test using 16 TFTs by converging threshold voltages with a target value by tuning the threshold voltage for each TFT.

How Does Parental Monitoring Reduce Adolescent Substance Use? Preliminary Tests of Two Potential Mechanisms.

The purpose of this study was to test two non-exclusive mechanisms by which parental monitoring might reduce teen substance use. The first mechanism (M1) is that monitoring increases punishment for substance use since parents who monitor more are more likely to find out when substance use occurs. The second mechanism (M2) is that monitoring directly prevents/averts teens from using substances in the first place for fear that parents would find out. A total of 4,503 teens ages 11-15 years old in 21 communities across the United States completed a survey reporting on parents' monitoring/knowledge and teens' substance use. We found no support for M1: Parents with greater parental monitoring were not more likely to be aware when the teen had used substances (odds ratios = 0.79-0.93, ps = .34-.85), so they could not have increased the rate of punishment. We found support for M2: When asked directly, teens identified instances in which they planned to or had a chance to use substances but did not because their parents got in the way or would have found out (p < .01). Had all those opportunities for substance use occurred rather than been averted by parents, the prevalence of substance use in the sample would have been 1.4 times higher. In this community-based sample of teens, we failed to support prior punishment-centric theories of how monitoring might reduce teen substance use. Rather, monitoring may directly discourage teens from using substances regardless of whether it increases parents' awareness of substance use or results in more punishment. Replication in other samples and contexts is needed.

Inline Determination of the Gel Elastic Modulus During Milk Coagulation Using a Multifiber Optical Probe

AbstractFrom a state-of-the-art point of view, it is currently possible to optically monitor the enzymatic coagulation of milk for real time estimation of the elastic modulus to cut the gel at optimum gel firmness. However, European cheese industry produces a wide variety of cheeses, many of them artisanal, and has a very fragmented productive structure with many small-, medium-sized companies. Therefore, if the technology is to be successfully uptake, it must be not only accurate but very low-cost. The objective of this work was to evaluate a low-cost commercial multifiber probe, for inline optical determination of curd firmness during cheese making. Preliminary tests were carried out to select the most appropriate fiber core size and wavelength and after that coagulation trials were performed following a fully randomized factorial design with two factors, i.e., concentration of protein (3.2, 3.6 and 4.0%) and added calcium (150, 200 and 250 mg L−1), with three replicates. The observed linear increase of the least square means of the initial voltage with the protein content (V0 = 0.15[P, %] + 0.88; R2 = 0.999), will be likely synergistic with the elastic modulus prediction if the model needs to be corrected for protein. Finally, the multifiber probe allowed predicting curd firmness using the proposed model with SEP values &lt; 7 Pa. The present work has proven that a low-cost multifiber probe is suitable for accurate, real-time prediction of curd firmness during cheese manufacture.

Fast Rock Detection in Visually Contaminated Mining Environments Using Machine Learning and Deep Learning Techniques

Advances in machine learning algorithms have allowed object detection and classification to become booming areas. The detection of objects, such as rocks, in mining operations is affected by fog, snow, suspended particles, and high lighting. These environmental conditions can stop the development of mining work, which entails a considerable increase in operating costs. It is vital to select a machine learning algorithm that is accurate, fast, and contributes to lower operational costs because of the aforementioned environmental situations. In this study, the Viola-Jones algorithm, Aggregate Channel Features (ACF), Faster Regions with Convolutional Neural Networks (Faster R-CNN), Single-Shot Detector (SSD), and You Only Look Once (YOLO) version 4 were analyzed, considering the precision metrics, recall, AP50, and average detection time. In our preliminary tests, we have observed that the differences between YOLO v4 and the latest versions are not substantial for the specific problem of rock detection addressed in our article. Therefore, YOLO v4 is an appropriate and representative choice for evaluating the effectiveness of existing methods in our study. The YOLO v4 algorithm performed the best overall, whereas the SSD algorithm performed the fastest. The results indicate that the YOLO v4 algorithm is a promising candidate for detecting rocks with visual contamination in mining operations.

Molecular and Serological Detection of Mycobacterium avium Subspecies Paratuberculosis in Ruminants of Jabalpur Region

Background: Paratuberculosis is a chronic infectious disease of wild and domestic ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP). The present study aimed to conduct the molecular and serological detection of MAP in ruminants of Jabalpur region. Methods: A total of 261 faecal, 124 blood and 51 tissue samples were collected from goats, buffaloes and cattle of the region irrespective of their age, sex and breed. ZN staining of faecal and tissue samples was performed as a preliminary screening test followed by anti-MAP antibodies detection in serum samples using indirect ELISA and IS900 PCR analysis of ZN positive faecal and tissue samples. Result: A pattern of acid-fast bacilli shedding in faecal samples of ruminants was obtained based on ZN staining with a majority of +1 shedders. In ELISA, 33.87% of serum samples were found positive for anti-MAP antibodies whereas, 22.50% ZN positive faecal samples and 100% ZN positive tissue samples were found positive in IS900 PCR. Therefore, a conclusion of moderately prevalent MAP infection in ruminants of the Jabalpur region can be drawn.

GNSS Radio Frequency Interference Monitoring from LEO Satellites: An In-Laboratory Prototype.

The disruptive effect of radio frequency interference (RFI) on global navigation satellite system (GNSS) signals is well known, and in the last four decades, many have been investigated as countermeasures. Recently, low-Earth orbit (LEO) satellites have been looked at as a good opportunity for GNSS RFI monitoring, and the last five years have seen the proliferation of many commercial and academic initiatives. In this context, this paper proposes a new spaceborne system to detect, classify, and localize terrestrial GNSS RFI signals, particularly jamming and spoofing, for civil use. This paper presents the implementation of the RFI detection software module to be hosted on a nanosatellite. The whole development work is described, including the selection of both the target platform and the algorithms, the implementation, the detection performance evaluation, and the computational load analysis. Two are the implemented RFI detectors: the chi-square goodness-of-fit (GoF) algorithm for non-GNSS-like interference, e.g., chirp jamming, and the snapshot acquisition for GNSS-like interference, e.g., spoofing. Preliminary testing results in the presence of jamming and spoofing signals reveal promising detection capability in terms of sensitivity and highlight room to optimize the computational load, particularly for the snapshot-acquisition-based RFI detector.

An adaptive Ritz formulation for progressive damage modelling in variable angle tow composite plates

In this work, an adaptive Ritz model for the analysis of variable angle tow composite plates featuring damage initiation and evolution under progressive loading is proposed, developed, implemented and tested. The plate kinematics is represented employing a first-order shear deformation theory, while the plate equilibrium equations at a given load step are obtained by minimizing the structure potential energy. The constitutive behaviour is modelled within the framework of continuum damage mechanics. In particular the initiation and evolution of damage, up to failure, are tracked by defining irreversible damage indices related to both fibres and matrix, both in tensile or compression loading. The discrete equations are then obtained by assuming a polynomial Ritz approximation of the primary kinematic variables in the energy minimization. Preliminary tests show how the application of the method as a single-domain approach induces the emergence of problematic spurious effects, related to Gibbs artefacts due to the inability of the selected polynomial basis to represent damage localization. An adaptive multi-domain technique is thus proposed to circumvent such issues, which has been successfully validated by benchmark tests. Eventually, original results about variable angle tow plates featuring damage evolution under progressive loading are presented.

Histopathological assessment of Atlantic salmon exposed to calcium oxide particles: a controlled clinical study

Particulate calcium oxide (CaO) has been successfully used for the control of sea urchin and starfish populations. Recent studies have proven its efficacy in killing planktonic copepods, making it a promising and cheap option for salmon louse control in the Atlantic salmon (Salmo salar) farming industry. Additionally, preliminary laboratory tests demonstrated that exposure to 0.2 g/L–0.6 g/L of fine CaO particles induced significant mortality of salmon louse (Lepeophtheirus salmonis) in the planktonic stages. The present study investigated the effects of water treatment with fine CaO particles [0.2 g/L or 127.4 g/m2; 0.1 mm–0.3 mm], conducted twice a week for three consecutive weeks at 5°C and 12°C on Atlantic salmon post-smolt in a flow-through system. The study compared mortality rates and histopathology of skin, eyes, gills, and intestines between treated and untreated control salmon. The results indicated that CaO exposure did not induce fish mortality or histopathological damages in the skin, eyes, or intestines. Although there were no significant effects of CaO exposure on gill inflammation or hyperplasia, the exposure did increase the occurrence of gill vascular injuries and necrosis in small portions of the tissue (&amp;lt; 10% of the respiratory gill tissue in most of the samples) by 60% and 35%, respectively. The effect was not modulated by temperature or time. The results indicate that the CaO treatment protocol used in this study is not lethal to Atlantic salmon and is safe for most analyzed tissues. Nonetheless, the induction of vascular damage and necrosis in the gill, albeit in small tissue portions, emphasizes the need for further research. It is crucial to develop a protocol that avoids such lesions, ensuring the secure application of CaO as an antiparasitic treatment in salmon aquaculture.

Self-Assembly and Antimicrobial Activity of Lipopeptides Containing Lysine-Rich Tripeptides.

The conformation and self-assembly of two pairs of model lipidated tripeptides in aqueous solution are probed using a combination of spectroscopic methods along with cryogenic-transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering (SAXS). The palmitoylated lipopeptides comprise C16-YKK or C16-WKK (with two l-lysine residues) or their respective derivatives containing d-lysine (k), i.e., C16-Ykk and C16-Wkk. All four molecules self-assemble into spherical micelles which show structure factor effects in SAXS profiles due to intermicellar packing in aqueous solution. Consistent with micellar structures, the tripeptides in the coronas have a largely unordered conformation, as probed using spectroscopic methods. The molecules are found to have good cytocompatibility with fibroblasts at sufficiently low concentrations, although some loss of cell viability is noted at the highest concentrations examined (above the critical aggregation concentration of the lipopeptides, determined from fluorescence dye probe measurements). Preliminary tests also showed antimicrobial activity against both Gram-negative and Gram-positive bacteria.

Possibilities of Increasing the Durability of Dies Used in the Extrusion Process of Valve Forgings from Chrome-Nickel Steel by Using Alternative Materials from Hot-Work Tool Steels.

This study refers to an analysis of the dies used in the first operation of producing a valve forging from chromium-nickel steel NC3015. The analyzed process of manufacturing forgings of exhaust valves is realized in the co-extrusion technology, followed by forging in closed dies. This type of technology is difficult to master, mainly due to the increased adhesion of the charge material to the tool substrate as well as the complex conditions of the tools' operations, which are caused by the cyclic thermo-mechanical loads and also the hard tribological conditions. The average durability of tools made from tool steel WLV (1.2365), subjected to thermal treatment and nitriding, equals about 1000 forgings. In order to perform an in-depth analysis, a complex analysis of the presently realized technology was conducted in combination with multi-variant numerical simulations. The obtained results showed numerous cracks on the tools, especially in the cross-section reduction area, as well as sticking of the forging material, which, with insufficient control of the tribological conditions, can cause premature wear of the dies. In order to increase the durability of forging dies, alternative materials made of hot work tool steels were used: QRO90 Supreme, W360, and Unimax. The preliminary tests showed that the best results were obtained for QRO90, as the average durability for the tools made of this steel equaled about 1200 forgings (with an increase in both the minimal and maximal values), with reference to the 1000 forgings for the material applied so far.

The buildability and flexural properties of 3D printed recycled mortar reinforced with synchronized steel cable under different reinforcement ratios

This study achieved the synchronized reinforcement of 3D printed mortar with steel cables by modifying the printing equipment. Recycled sintered brick powder replaced 30 % of cement in the 3D printed mortar mixture. The optimal range for the open time was determined through flowability tests and preliminary tests, which ranged from 10 to 40 min. Ways to improve the reinforcement ratio without compromising buildability were explored. The bond strength between the steel cables and the printed mortar was tested and found to be approximately 2–2.5 MPa. The flexural strength of the printed beams with steel cable reinforcement increased by 172%–357 %, and multiple cracks occurred at the mid-span during the failure process. A correction formula for the flexural strength was provided, with calculated values showing an error within 12 % of the test values.

The Use of Graphic Organizer Strategies to Improve Students' Writing Skills in English Language Teaching

This research is motivated by the weak ability of students' writing in learning English. This research was conducted with the aim of improving English language skills, especially writing skills through the use of the graphic organizer strategy. This research was conducted on first semester students at Billfath Lamongan University. The subjects of this research were students of the English program from several research programs totaling 34 students. This research uses a Classroom Action Research design by Kemmis and Mc Taggart model in four stages, namely planning, implementing action, observing, and reflecting. The results of the preliminary test showed that students' writing skills were still low. The results of the assessment on the practice of writing texts using the assessment rubric show that there are still many students who have not reached the mark according to the criteria. The percentage of scores obtained by students are dominated by the "poor" criterion with 41%, fair 32%, good 18%, very poor 9%, and excellent 0%. While, the students' competence increased and has reached the specified minimum completeness criteria in the final test. The percentage of scores obtained by students are dominated by the "good" criterion with 50%, excellent 32%, fair 18%, poor 0%, and very poor 0%. The results of this research prove that the use of the graphic organizer strategy significantly improves students' writing skills and also has a positive impact on students' attitudes toward learning English.