Experimental Investigation on Influence of Molding Methods on Properties of Pervious Concrete

Despite the common use of pervious concrete (PC), there is no standard way of producing the test specimens, which undergo testing to infer the behaviour of PC in the field. Vibrating table is the most common method but greatly reduced in vibration time compare with normal concrete in the laboratory. Marshall compaction and superpave gyratory compactor (SGC) are recommended standard molding methods for porous asphalt mixtures manufactured in the laboratory environment. Three kinds of pervious concrete samples with three target porosities were prepared by the above three methods, and the effects of the molding method on the physical properties, mechanical properties and durability of the samples were investigated in the study. Experimental results showed, with different molding methods adopting, pervious concrete with the same mixture design exhibits slightly different physical and mechanical properties. After analysis and comparison, SGC is the best choice to obtain concrete with high permeability, good freeze-thaw resistance and high strength, followed by Marshall compaction molding, and vibration molding is the last one. As a result, a win-win situation of the hydraulic characteristics and mechanical properties of pervious concrete can be achieved due to both optimized mix-design and appropriate molding method.

Optimisation of the magistral semisolid formulations with furazidine used in urogenital infections

Background: Urinary tract infections are the most common urogenital diseases, with an increased incidence in men and older people. Urogenital infections are caused by Gram-negative bacteria, in which Escherichia coli predominates with a share of 80%. The evolution of microbial resistance to preparations used in curative-prophylactic institutions, induces the need of the reintroduction of nitrofurans, noteworthy for their wide spectrum of antibacterial activity. Material and methods: For the study, suppositories with furazidine were prepared by hand rolling and by melting and molding methods. Quantitative analysis was performed spectrophotometrically on a UV-VIS Perkin Elmer Lambda 40 spectrophotometer. All solvents and reagents had the degree of purity ”pure for analysis” and ”chemically pure”. Results: Duble cast method was applied to identify the exact mass of hydrophobic (cocoa butter, suppocire) and hydrophylic (polyethylene glycol mixtures) excipients. All the formulated suppositories were subjected to quality tests and showed acceptable physical characteristics and uniformity of drug contents. The UV-VIS spectrophotometric method for quantitiative determination of furazidine was developed and validated. The validation results showed that the developed method is simple, fast, accurate and robust. Conclusions: Suppositories with furazidine were prepared by classic technological methods. Preparation of the suppositories with furazidine on cocoa butter excipient is a suitable alternative for individual medicinal prescriptions. The UV-VIS spectrophotometric dosing method for furazidine in suppositories was developed and validated

Effect of Aluminum Flakes on Mechanical and Optical Properties of Foam Injection Molded Parts

Injection research using aluminum flakes has been conducted to realize metallic textures on the surface of plastic products. Several studies have focused on the effect of the orientation and quality of the flakes when using conventional injection molding methods; however, limited studies have focused on the foam injection molding method. In this study, we examined the orientation of aluminum flakes through foam injection with an inert gas and observed the changes in texture using a spectrophotometer and a gloss meter. The mechanical properties were also studied because the rigidity of the product, which is affected by the weight reduction that occurs during foaming, is an important factor. The results demonstrate that under foam injection molding, reflectance and gloss increased by 6% and 7 GU, respectively, compared to those obtained using conventional injection molding; furthermore, impact strength and flexural modulus increased by 62% and 15%, respectively. The results of this research can be applied to incorporate esthetic improvements to products and to develop functional parts.

Perancangan Klem Untuk Cetakan Vertical Pouring Di Laboratorium Pengecoran Logam Politeknik Manufaktur Bandung

In the foundry laboratory at Bandung Polytechnic for Manufacturing, there is a student practicum program where the student learns several molding methods that are often used. One of these methods is a vertical pouring method. This is a one of mold method in the foundry process where the object is positioned vertically (vertically) with the inlet position either at the bottom of the object or at the top of the object. In this experiment using the vertical pouring method with direct pouring from a top. This method is usually used for objects that are plate shaped or cylindrical. The advantage of this method can control shrinkage and minimizes the mold area. In the process, where the object will be made in limited quantities, the mold is tied and buried in sand. The problems are processing time is longer than Cup and Drug molds, and wears a lot of sand. For this reason, a tool for clamping vertical molds is designed. This tool is expected to reduce use of sand, and reduce processing time. This tool is made of steel. vertical pouring method becomes more effective and efficient by using clamps

THE USE OF THERMOSETTING MATRICES FOR THE MANUFACTURE OF POLYMER COMPOSITE MATERIALS BY THE NON-AUTOCLAVE MOLDING METHODS

In work, the rheological heat-resistant and elastic-strength characteristics of thermosetting systems developed at FSUE «VIAM» (epoxy matrices of grades VSE-20, VSE-30, VSE-33, bismaleimide grade VST-57 and cyan ester matrices of grades VST-1210 and VST-60) processed by non-autoclave technologies. These resins make it possible to obtain composite materials for structural purposes with an operating temperature from -60 to 250 °C by the methods of vacuum infusion, impregnation under pressure and film technology. The work also presents glass transition temperatures and mechanical properties of carbon and fiberglass plastics obtained on their basis.

The Effect of Thermal Degradation Processes on the Physical-Mechanical and Rheological Properties of Polyketone

The effect of polyketone thermal processing duration on the rheological properties of the melts and the physical and mechanical characteristics of the samples, obtained by injection and compression molding methods, is studied.

Evaluation of bacterial diversity during fermentation process: a comparison between handmade and machine-made high-temperature Daqu of Maotai-flavor liquor

Purpose High-temperature Daqu is a traditional fermentation starter that is used for Chinese Maotai-flavor Baijiu production. Although the bacteria in high-temperature Daqu are known to be responsible for developing the quality and flavor of Baijiu during the fermentation process, there is little information on the properties of the bacteria during the fermentation of high-temperature Daqu, especially machine-made high-temperature Daqu. This has limited the development of the Maotai-flavor Baijiu industry, particularly with regard to the mechanized production of Maotai-flavor Baijiu. Methods Illumina MiSeq high-throughput sequencing was applied to study bacterial compositions during the fermentation of handmade and machine-made high temperatures. Results The results show that bacterial diversity in machine-made Daqu was similar but higher than that in handmade Daqu at the end of fermentation, and there was no significant difference between the methods with regard to the dominant genera and their dynamic changes during fermentation. Rhizobium, Bacillus, Thermoactinomyces, Weissella, Lactobacillus, and Saccharopolyspora were the dominant genera during the fermentation of both Daqus, although the relative abundance of these dominant genera differed between the two methods. Interestingly, the machine-made Daqu contained a higher relative abundance of Bacillus than handmade Daqu at all fermentation times. Bacillus is the most important functional bacteria in the fermentation of Maotai-flavor Baijiu, suggesting that mechanical-molding methods could be applied to industrial Maotai-flavor Daqu production. Conclusion These results suggest that mechanical-molding methods could be applied to industrial Maotai-flavor Daqu production, which could be helpful for industrial Maotai-flavor Baijiu production and the development of fermentation technology.