The effect of repeated laundering on the softness and smoothness of terry-cloth towels using a sound spectrum analysis

PurposeThis study aims to examine the effect of laundering on the softness and smoothness of terry-cloth towels by different washing machine type, washing temperature, drying method and the use of fabric softener, using a newly developed sound spectrum analysis known as Textile Softness Analyzer.Design/methodology/approachThe experiment was designed to analyze the most significant laundering parameter in the reduction of softness and smoothness of terry cloth during one laundering cycle up to ten cycles by testing samples using TSA machine.FindingsA front-loading washer had a significant effect on reducing softness and smoothness in comparison to a top-loading machine; line-drying resulted in a higher decrease in softness and smoothness than tumble-drying. Washing temperature showed no significant effect, and the use of softener during washing was able to reduce the negative effect of line-drying on the softness and smoothness of terry cloth.Originality/valueThis paper provided information on the laundering parameters that can maintain the softness and smoothness of terry-cloth towels, and this was examined with sound spectrum analysis to measure softness and smoothness of textiles.

Fracture resistance of mollars with MOD cavities restored with different materials

Restoring teeth with second class cavities is a challenge in dentistry. Both the carious process and the preparation of the cavity for the dental restoration reduces the tooth resistance to the masticatory forces. It has been shown that modern aesthetic materials using an adhesive system improve the stress resistance of the restored teeth. There is a series of studies that attempted to determine the type of optimal material that would provide increased resistance to occlusal demands. In the present study we tried to determine the fracture resistance of molars with second class cavities restored with different categories of aesthetic materials. Thus, forty intact molars were divided into five groups of 8 teeth, MOD cavities were prepared and the teeth were restored with three types of materials: nanofilled composite, mycrohibrid composite and ormocer. The teeth of the first group were left unprepared, and those belonging to the second group were subjected to the preparation of MOD cavities but were not filled. Samples were subjected to compression using an Universal Loading Machine (Lloyd Instruments) and the value of the force they failed was recorded. Intact teeth showed the highest resistance to compression and those with MOD cavities prepared but not filled showed the smallest. Of the groups that benefited from restoration with filling material, the teeth restored with ormocer had the highest resistance, followed by those restored with nanofilled composite, and finally by those restored with mycrohibrid composite.

Kinematics of the Maneuver of the Multifunctional Machine for Metallurgical Furnaces

The article proposes a simulation model of a loading machine for metallurgical furnaces and builds a mathematical model that makes it possible to find optimal trajectories of motion and obtain laws of change in kinematic, dynamic and inertial characteristics for a full operation cycle. The description of the machine motion is made taking into account the nonholonomy of the imposed connections and provides for the possibility of considering arbitrary laws of motion along optimal trajectories. Compliance with optimal working conditions is also ensured by the choice of a special law of motion between the nodal points on the trajectory of movement, corresponding to the change in the direction of movement of the loading machine. Based on the research results, a design scheme and a simulation model with an analytical description of the mechanism operation, including kinematic graphs, are proposed. A simulation model of a loading machine for metallurgical furnaces and a description of its operation modes are made by methods of analytical mechanics.

Comparison of Classic and Metal Reinforced Maxillary Acrylic Complete Dentures Fracture Resistance

The aim of our study was to evaluate fracture resistance of the PMMA complete dentures and to make a comparison between the classic acrylic maxillary complete dentures and the metal-reinforced ones, in terms of fracture resistance during function and to compare the fracture pattern of the two groups of complete dentures. We used maxillary complete dentures made of heat-processed acrylate, 5 exclusively and 5 in which a metal-cast net in the form of a mesh was inserted after being casted, worn by patients for a period of 5 years. A bilateral progressive force was applied to the PM2-M1 area until the samples failed, recording the force value at which the first change occurred. A Universal Loading Machine was used. The results were analyzed using the ANOVA method. For the classic acrylic complete dentures group, the minimum fracture force value was 1060 N, the maximum fracture force value being 2443 N. For the reinforced complete dentures group, the minimum fracture force value was 3320 N, the maximum value being 3760 N. Statistical analysis of data using the ANOVA shows that the results are statistically relevant, with a p value of 0.000137 (p[0,05). All the dentures from the classic acrylic complete dentures group fractured presenting two or more fracture lines, most of them involving also fractures on the acrylic teeth and breaking into multiple pieces, while all the dentures from the reinforced complete dentures group fractured presenting one or two fracture lines, most of them without detachable fragments and involving also fractures on the acrylic teeth.