TOJSAT - Volume 9 - Issue 3 - July 2019

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INVESTIGATION OF FACTORS AFFECTING SURFACE ROUGHNESS OF HEAT TREATED 5040 STEEL BY EXPERIMENTAL DESIGN METHOD

Ayhan AYTAÇ, Muhammed İLİVAN

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Abstract:

One of the main problems to be tried to solve in machining is machinability.
Manufacturer seeks answer of how he can produce his product cheaper and more quality. One
of the main purposes in machining is to bring surface roughness to the top level. The stage
where the most decisive work can be done in improving the product quality is the parameter
design phase for both product and process design. In order to determine the most effective
parameters and to evaluate the results more efficiently, the Taguchi experiment design
technique is preferred to realize the experiments in a shorter time. This performed study was
done by the aim of investigating the effect of change in terms of hardness, feed rate, and
cutting tool of “Dual Phase” steel, which is a class of HSLA (High Strength Low Alloy) steels
that increases usage and importance day by day, on surface quality in turning process in the
pieces subjected to reasonable forces in machine, device, car manufacturing. Experimental
design In the Minitab statistical analysis program, Taguchi experiment design technique and 9
trials according to L9 orthogonal design. Experiments were performed in dry cutting
conditions in CNC Turning Table that has 1.5 kW power and rotates with maximum 2000
rpm. Variance analysis and signal / noise ratio were used in the evaluation of the test results. .
It was possible to achieve the intended results with only one third of the number of
experiments required in full factorial design (9 experiments instead of 27). In the experiments,
the cutting tool type (CBN, Ceramic and Carbide cutter), the feed rate (0,02, 0,04 and 0,06
mm/cycle) and the material hardness (Material with three different hardness values obtained
by annealing at 745, 760, and 775 degrees obtained after heat treatment) were used as the
independent variable (factor). The mean surface roughness value (Ra) as a dependent variable
was determined from measurements taken at 6 different points in three trials. As a result, the
most effective parameters on the surface quality are the feed rate, the material hardness
(microstructure) and the cutting tool. The results obtained are interpreted together with the
evaluations which have been entered into the literature before.

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NITROREDUCTASES FROM THERMOPHILIC BACILLUS SPECIES

Kemal GÜVEN, Fatma MATPAN BEKLER, Reyhan GÜL GÜVEN

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Abstract:

Nitroreductases (NTR) are members of the NAD(P)H/FMN oxidoreductase that
exists widely in bacteria. NTRs have raised a great interest due to their potential in
biomedicine, especially in prodrug activation for chemotherapeutic cancer treatments, in
bioremediation and enzyme-based biosensors for nitro-sensitive compounds. Thermophilic
Bacillus species isolated from hot water springs in Turkey were identified by 16S rRNA gene
sequence analysis. The previously identified species, Bacillus paralicheniformis (5NK) and
Bacillus paralicheniformis (FMB2) with sequence similarity of 97% and 99.65, respectively,
were used. They were all found to possess the putative NADPH nitroreductase genes. Genomic
DNAs for isolation of nitroreductase genes were isolated by conventional phenol-chloroform
extraction method. The nitroreductase genes from thermophilic Bacillus species were
amplified by PCR, using the designed three primer pairs. The corresponding DNA fragments
were fractionated by agarose gel electrophoresis and PCR products were purified and
concentrated for cloning and DNA sequencing.

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PROTECTING MASONRY SURFACES FROM MOLD GROWTH WITH MINIMUM RISK ANTIMICROBIAL AGENTS

Benton Allen, Emily M. Hunt

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Abstract:

Sanitation efforts in public institutions quietly operate behind the scenes to ensure
comfort and safety of the building occupants. Without extremely consistent, detail oriented
service, the aesthetic appeal and sanitation of surfaces can quickly deteriorate to a level that
puts the occupants of a building at risk. Public restrooms are one of the most missioncritical
areas in a janitorial regimen due to the number of revolving occupants and the
activities conducted therein. Though a significant amount of research has been dedicated to
developing sanitary architectural design practices, many of these practices were not utilized
in prior construction and are not being adopted in new construction. This creates a critical
and immediate need for coatings and sealants that can aid janitorial efforts in keeping
surfaces clean and hygienic. Researchers from West Texas A&M University (Canyon,
Texas, USA), in collaboration with Buffalo Technology Group LLP (Canyon, Texas, USA)
explored several mixtures of antimicrobial additives that could be incorporated into
commercially available masonry sealants to provide tile grout and other masonry surfaces
with protection from fungi and bacteria. These additive mixtures were subjected to
standardized microbiologically testing procedures against mold (Aspergillus niger) by agar
diffusion disk method. Results from microbiological testing indicate that the sealants
enhanced with the antimicrobial additives could provide surfaces that are inhospitable to
fungi growth and propagation. These results are significant because the additive material
eliminates the primary sources of aesthetic and hygienic contamination on masonry
surfaces in public areas and can be easily and safely applied to existing and new surfaces
without the additional environmental concerns of common sterilizing cleaners.

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THE USE OF NEW TECHNOLOGIES IN THE ELDERLY IN THE NORTH OF PORTUGAL

Vitor RODRIGUES, Marta GONÇALVES, Arsénio REIS, Carlos TORRES, Maria João MONTEIRO, João BARROSO, Tiago RODRIGUES, Hugo PAREDES, Vitor FILIPE, Rui XAVIER

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Abstract:

The elderly, especially those living in institutions, tend to have many health
limitations, such as reduced vision, hearing and locomotion, which necessarily implies the risk
of loneliness. An exploratory and cross-sectional study was carried out. Data collection took
place between February and May 2018, in 5 residential structures for the elderly in the north
of Portugal. The study included 130 elderly people, 68,5% female and 31,5% male, with an
average age of 82,43 years and an average stay in the institution of 4,5 years and 57,7% are
widowers. 43,1% of the elderly would see a robot that interacted with them as interesting and
very interesting. The data found in this study shows that it is essential to provide the elderly
with new forms of social relationships with the help of new technologies in order to avoid
loneliness and to contribute to a better quality of life.

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