Experimental Investigation and Numerical Analysis Regarding the Influence of Cutting Parameters on the Asphalt Milling Process.

Abrasion wear is a significant concern for cutting tools, particularly when milling asphalt concrete due to the presence of hard mineral aggregate particles. The pressure exerted on the cutting tool by the chipped material and the resulting cutting forces directly influence tool wear. To estimate the cutting forces in asphalt milling, the authors propose using either laboratory experiments or cost-effective Discrete Element Method (DEM) modeling-by simulating the real conditions-as direct measurement under real conditions is challenging. This article presents results from an original experimental program aimed at determining the cutting forces during asphalt pavement milling. A specialized stand equipped with a moving plate and recording devices was designed to vary milling depth, rotational speed, and advance speed. The experimental results for horizontal force values were compared with numerical results from DEM modeling. It was found that both increasing the milling depth and the advance speed lead to higher cutting forces. Generally, DEM modeling trends align with experimental results, although DEM values are generally higher. The statistical analysis allowed identification of the milling depth as the most significant parameter influencing cutting force and the optimal combination of milling parameters to achieve minimum horizontal force acting on cutting tooth, namely, 15 mm milling depth and 190 mm/min advanced speed.

The Benefits of a Comprehensive Cardiac Rehabilitation Program for Patients with Acute Coronary Syndrome: A Follow-Up Study.

BACKGROUND AND OBJECTIVES: Secondary prevention after acute coronary syndrome (ACS) is essential to reduce cardiovascular mortality and hospital readmission, ensuring patients return to normal with an improved quality of life. Thus, we investigate the benefits of a comprehensive cardiac rehabilitation (CR) program on lifestyle, risk factors and adherence to guideline-directed medical therapy (GDMT) in patients after ACS and myocardial revascularization through coronary artery by-pass grafting (CABG) or percutaneous coronary intervention (PCI). METHODS: This is a prospective, longitudinal study in consecutive post-CABG or PCI patients after ACS that participated or not in a comprehensive CR. Cardiovascular risk factors, quality of life and adherence to GDMT were analyzed in terms of assessing the benefit of 12 months of comprehensive CR on reaching guidelines secondary prevention targets. RESULTS: At the inclusion in comprehensive CR of all patients (n = 480), 85% had hypertension; 86% had elevated total cholesterol values; 69% were characterized by metabolic syndrome; 43% were obese; 31% were active smokers and 29% had type 2 diabetes mellitus. Only 26.66% (n = 128) followed the entire program for 12 months. No statistically significant differences in the prescription of GDMT at hospital discharge after myocardial revascularization between the CR (+) group (n = 128) versus CR (-) group (n = 352) (p > 0.05) were observed. After 12 moths, a significant adherence to GDMT in the CR (+) group vs. CR (-) group was recorded, as follows: antiplatelet agents (100% versus 96%, p = 0.001), beta-blockers (99% versus 92%, p = 0.02), ACE inhibitors/ARAB (89% versus 79%, p = 0.04), lipid-lowering drugs (100% versus 89%, p = 0.001). In total, 82% of the CR (+) patients had a significantly higher adherence at GDMT (82% versus 64%, p = 0.001). At 12 moths, the CR (+) group was characterized by significantly lower values than at the inclusion but some values still increased: systolic blood pressure (139.25 + 19.20 mmHg (p < 0.03)), total cholesterol (171.07 + 48.59 mg/dL (p = 0.0001)) and LDL-cholesterol (102.83 + 41.30 mg/dL (p = 0.009)). At the same time, the analysis of psychosocial factors using the HAD questionnaire revealed a statistically significant improvement in anxiety and depression scores: HAD-A score (9.1 ± 3.7 at T0 vs. 7.1 ± 4.2 at T1, p = 0.001) and HAD-D score (7.7 ± 3.19 at T0 vs. 6.4 ± 4.3 at T1, p = 0.003). A multivariable analysis, following GDMT, showed the actual value or information and training of patients regarding optimal cardiovascular risk factor control was independently associated with lower values of systolic blood pressure (R2 = 0.48), diastolic (R2 = 0.38), serum glucose (R2 = 0.48), glycated hemoglobin (R2 = 0.50), total cholesterol (R2 = 0.31), LDL-cholesterol (R2 = 0.30), HDL-cholesterol (R2 = 0.19) and serum triglycerides (R2 = 0.20). CONCLUSION: The twelve-month participation of post-ACS patients in comprehensive CR resulted in excellent post-revascularization management, as well as good adherence to guideline-directed medical therapy, provided further confirmation of the benefit of secondary prevention. Despite high adherence to drug treatments, targets for blood pressure, total cholesterol and LDL-cholesterol are inadequately achieved. Therefore, in the era of personalized medicine, patients with ACS should benefit from specific, comprehensive cardiovascular recovery programs that contain physiotherapists, psychologists, nutritionists and an experienced cardiologist in cardiovascular rehabilitation.

Experimental Research Regarding the Effect of Mineral Aggregates on the Wear of Mixing Blades of Concrete Mixers.

Industrial mixers are equipment used to mechanically combine different types of materials in order to obtain homogeneous mixtures. In concrete industry production, mixers play a crucial role by facilitating the efficient and consistent blending of various constituents to create high-quality concrete. Because the mixers in the concrete industry work in conditions characterized by abrasive and erosive loadings, the authors of this paper tried to establish a dependence between the quality of the material from which the mixing elements are made and their wear resistance. Three types of cast irons alloyed with chromium, specific to the construction of mixing blades, were used in this research. The working environment was a mixture of crushed mineral aggregates corresponding to the granulometric class 4-8 mm. The tests were carried out on an experimental stand designed and built by the authors of this paper. The stand reproduces on a scale of 1:2 a drum made up of a double-axis horizontal mixer. The stand had the possibility to change the value of the attack angle of the mixing blades, corresponding to the following values: 30, 45, and 60 degrees. The results of the tests established the dependence between the type of material and the wear rate of the blades as well as the influence exerted by the angle of attack on the wear of the mixing blades. It was shown that when the inclination angle of the blade relative to the shaft axis increases, the cumulative mass loss decreases, with values between 43% and 55.83%, as a function of the quality of blade material.

Experimental Research on the Wear Behavior of Materials Used in the Manufacture of Components for Cement Concrete Mixers.

Mixers used in the production of cement concrete operate under special conditions such as mechanical stresses, abrasive-erosive friction phenomena, and corrosive working environments. In this paper, the authors aimed to establish a correlation between the chemical composition of mixer blade materials and their wear behavior. Three types of alloyed (chromium) cast iron were used for an experimental program that included three sets of tests in accelerated wear conditions which replicated the actual working environment (mixture of mineral aggregate, sand, cement, and water). The tribological tests were carried out using a Baroid tribometer. The results indicated that regardless of the test environment, cast iron with the highest chromium content exhibited the best wear resistance. However, it cannot be concluded that the wear resistance of the studied cast iron materials increases as a direct result of an increase in chromium content. For a chromium content of less than 25%, a better tribological behavior was observed for cast iron with a lower chromium content (of about 4%) than for cast irons with a higher chromium content (of about 9%).

Evaluation of Psychological Stress Parameters in Coronary Patients by Three Different Questionnaires as Pre-Requisite for Comprehensive Rehabilitation.

BACKGROUND: Negative psychological conditions are common in patients with cardiovascular diseases. Although depression has been scrutinized over the years in these patients, only recently has anxiety emerged as another important risk factor. The purpose of this study was to compare the parameters of psychological stress in a population of coronary patients with and without myocardial revascularization procedures and to analyze lifestyle and socio-economic contributors to the state of health of these patients before inclusion in a comprehensive individualized rehabilitation program. METHODS: This study included 500 patients with coronary artery disease (CAD) in stable condition divided in 2 groups: 200 patients who underwent coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA) (Group 1) and 300 patients without myocardial revascularization (Group 2) with stable angina or thrombolyzed myocardial infarction. The protocol included screening for anxiety/depression after procedure using three different scales: Duke Anxiety-Depression Scale, Hospital Anxiety and Depression Scale (HADS) and the Type D Personality Scale (DS-14) scale that evaluates negative affectivity (NA) and social inhibition (SI). RESULTS: Significant differences between groups were observed for HAD-A (9.1 ± 4.18 for Group 1 vs. 7.8 ± 4.03 for Group 2, p = 0.002) and DUKE scores (30.2 ± 12.25 for Group 1 vs. 22.7 ± 12.13 for Group 2, p < 0.001). HAD-A scores (p = 0.01) and DUKE scores (p = 0.04) were significantly higher in patients who underwent PTCA vs. CABG. CAD patients without myocardial revascularization (Group 2, n = 300) presented anxiety in proportion of 72.3% (n = 217) out of which 10.7% (n = 32) had severe anxiety, and 180 patients had depression (a proportion of 60%) out of which 1.3% (n = 4) presented severe depression. The correlation between the presence of type 2 diabetes mellitus (T2DM) and type D personality in revascularized patients (n = 200) was significant (Chi2 test, p = 0.010). By applying multinomial regression according to the Cox and Snell R-square model and multivariate linear regression by the Enter method, we demonstrated that male gender, age and marital status proved significant predictors for psychological stress in our study population. CONCLUSIONS: The results obtained in this study provide a framework for monitoring anxiety, depression and type D personality in coronary patients before inclusion in comprehensive rehabilitation programs. Behavioral and psychological stress responses in patients with CAD significantly correlate with risk factors, and could influence the evolution of the disease. Moreover, other factors like gender, income and marital status also seem to play a decisive role. Evaluation of psychological stress parameters contributes to a better individualization at the start of these programs, because it allows adjusting of all potential factors that may influence positive outcomes.

The Importance of DS-14 and HADS Questionnaires in Quantifying Psychological Stress in Type 2 Diabetes Mellitus.

Background and Objectives: The comorbid association between type 2 diabetes mellitus (T2DM) and a psychological profile characterized by depression and/or anxiety has been reported to increase the risk of coronary heart disease (CAD), the most striking macrovascular complication of diabetes. The purpose of the present study was to quantify anxiety, depression and the presence of type D personality, and to correlate the scores obtained with cardiovascular risk factors and disease severity in diabetic patients. Materials and methods: The retrospective study included 169 clinically stable diabetic patients divided into two groups: group 1 without macrovascular complications (n = 107) and group 2 with CAD, stroke and/or peripheral vascular disease (n = 62). A biochemical analysis and an assessment of psychic stress by applying the Hospital Anxiety and Depression Scale (HADS)and the Type D scale (DS-14) to determine anxiety, depression and D personality scores were done in all patients. Statistical analysis was made using SPSSv17 and Microsoft Excel, non-parametric Kruskal-Wallis and Mann-Whitney tests. Results: Following application of the HAD questionnaire for the entire group (n = 169), anxiety was present in 105 patients (62.2%), and depression in 96 patients (56.8%). Group 2 showed significantly higher anxiety scores compared to group 1 (p = 0.014), while depression scores were not significantly different. Per entire group, analysis of DS-14 scores revealed social inhibition (SI) present in 56 patients (33%) and negative affectivity (NA) in 105 patients (62%). TheDS-14 SI score was significantly higher in group 2 compared to group 1 (p = 0.036). Type D personality, resulting from scores above 10 in both DS-14 parameter categories, was present in 51 patients of the study group (30%). There was a direct and significant correlation (r = 0.133, p = 0.025) between the Hospital Anxiety and Depression Scale-Anxiety (HAD-A) score and the LDL-c values. Conclusions: The results of this study demonstrated that more than a half of patients with diabetes had anxiety and/or depression and one third had Type D personality, sustaining that monitoring of emotional state and depression should be included in the therapeutic plan of these patients. New treatment strategies are needed to improve the well-being of diabetic patients with psychological comorbidities.

Correlations between Vascular Stiffness Indicators, OPG, and 25-OH Vitamin D3 Status in Heart Failure Patients.

Background and objectives: The purpose of the study is to correlate vascular calcification biomarkers osteoprotegerin (OPG) and 25-hydroxyvitamin D3 (25-OH-D3), indicators of arterial stiffness carotid-femoral pulse wave velocity (c-f PWV) and renal resistive index (RRI), with parameters of left ventricular function in heart failure patients versus control. Materials and methods: Our case-control study compared 60 patients with ischemic heart failure and reduced left ventricular ejection fraction (LVEF) (<40%) with a control group of 60 healthy age-matched subjects (CON). Serum levels of OPG and 25-OH-D3 were determined by ELISA. Left ventricular volumes (LVESV, LVEDV) and LVEF were measured by echocardiography. C-f PWV was determined using the arteriograph device. RRI was measured by duplex Doppler. Peak systolic velocity (PSV) and minimum end-diastolic velocity (EDV) were determined using angle correction. The estimated glomerular filtration rate (eGFR) was calculated using the MDRD equation. The Pearson's correlation coefficient was used for interpretation of results. Results: OPG values were significantly higher in heart failure (HF) patients vs. CON (4.7 ± 0.25 vs. 1.3 ± 0.67 ng/mL, p < 0.001). 25-OH vitamin D3 levels were significantly lower in HF patients vs. CON (20.49 ± 7.31 vs. 37.09 ± 4.59 ng/mL, p < 0.001). Multiple regression analysis considering 25-OH D3 as a dependent variable demonstrated indicators of vascular stiffness RRI, c-f PWV and vascular calcification biomarker OPG as predictors. OPG values were significantly correlated with cardiac parameters LVEDV (r = 0.862, p < 0.001), LVEF (r = -0.832, p < 0.001), and c-f PWV(r = 0.833, p < 0.001), and also with 25-OH-D3 (r = -0.636, p < 0.001). RRI values were significantly correlated with cardiac parameters LVEDV (r = 0.586, p < 0.001) and LVEF (r = -0.587, p < 0.001), and with eGFR (r = -0.488, p < 0.001), c-f PWV(r = 0.640, p < 0.001), and 25-OH-D3 (r = -0.732, p < 0.001). Conclusions: This study showed significant correlations between vitamin D deficit and vascular stiffness indicators in heart failure patients with reduced ejection fraction, demonstrating the importance of these examinations for a better evaluation of these patients. Together with the evaluation of renal function, the measurement of vascular stiffness indicators and biomarkers might play a key role in identifying patients at greater risk for worsening disease prognosis and for shorter life expectancy, who could benefit from vitamin D supplementation. The abstract was accepted for presentation at the Congress of the European Society of Cardiology, Munich, 2018.

Perception of Organic Food Consumption in Romania.

This study provides insight into the attitude of Romanian consumers towards organic food. Furthermore, it examines the sustainable food production system in Romania from the perspective of consumer behavior. This study used a mathematical model of linear regression with the main purpose being to determine the best prediction for the dependent variable when given a number of new values for the independent variable. This empirical research is based on a survey with a sample of 672 consumers, which uses a questionnaire to analyze their intentions towards sustainable food products. The results indicate that a more positive attitude of consumers towards organic food products will further strengthen their purchasing intentions, while the status of the consumption of organic consumers will not affect their willingness to purchase organic food products. Statistics have shown that sustainable food consumption is beneficial for health, so it can also become a profitable business in Romania. Furthermore, food sustainability in Romania depends on the ability of an organic food business to adapt to the new requirements of green consumption.