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Fulltext The influence of sulphuric acid concentration on hard anodising process on powder metallurgy Al-Mg

Mohd Nazree Derman, Mohd Nasuha Abd Halim, Shaiful Rizam Shamsudin

Journal of Nuclear and Related Technologies, 2009;2009(1):224-229.
MyJurnal

The hardcoat anodising process was done by using different concentration of H2SO4 from 0% to 20%. The 90 volt of anodising process was applied by using Al foil as cathode materials. The surface changes on PM Al-Mg resulted by hardcoat anodising was characterised by XRD measured. Surface hardness was measured by Micro-Vickers hardness machine. The experiment found different XRD pattern between anodised PM Al-Mg samples. The study was found by that the optimum value for H2SO4 concentration was 15 % H2SO4 and result 26 μm thickness, 5.07% of mass changes and HVN 105.4 hardness. The hardcoat anodising was affected to the XRD pattern for PM Al-Mg.

Matched MeSH terms: Hardness
Fulltext Al/b4c composites with 5 and 10 wt% reinforcement content prepared by powder metallurgy

Yusof Abdullah, Mohd Reusmaazran Yusof, Azali Muhammad, Nadira Kamarudin, Paulus, Wilfred Sylvester, Nurazila Mat Zali, et al.

Journal of Nuclear and Related Technologies, 2012;2012(1):42-47.
MyJurnal

The preparation, physical and mechanical properties of Al/B4C composites with 5 and 10 wt.% reinforcement content were investigated. In order to obtain the feedstock with a low powder loading, B4C mixtures containing fine powders were investigated to obtain the optimal particle packing. The experimental results indicated that the fine containing 5 and 10 wt.% particles are able to prepare the feedstock with a good flowability. The composites fabricated by powder metallurgy have low densities and homogeneous microstructures. Additionally there is no interface reaction observed between the reinforcement and matrix by XRD analysis. The hardness of Al/B4C composites prepared by powder metallurgy was high.

Matched MeSH terms: Hardness
Fulltext Improvement of mechanical properties and fatigue failure of Spot-Welded joint through Pneumatic Impact Treatment (PIT)

Ghazali, F.A., Salleh, Z., Hyie, K.M., Taib, Y.M., Nik Rozlin, N.M.

Pertanika Journal of Science & Technology, 2017;25(108):105-114.
MyJurnal

This study focuses on examining the influence of post weld impact treatment (PWIT) using Pneumatic Impact Treatment (PIT) for spot welded joint on mechanical properties and fatigue failure. PWIT is one of the methods for improving mechanical properties and fatigue strength of welded joints. One of the versatile techniques of PWIT used for this study is PIT. The material investigated in this study was carbon steel with welded single lap shear joint with the constant thickness of 1.2mm. All the welded samples were later performing the tensile shear test, hardness test, and fatigue test. The tensile shear test was conducted on the spot welded both treated and untreated samples using crosshead speed of 2 mm/ min, while hardness test was performed using 1kgf load via Vickers hardness indenter. Fatigue test was conducted using R=0.1 and frequency of 10 Hz. The effects of PIT on tensile-shear properties, hardness, and fatigue failure were evaluated. It was found that the implementation of PIT has increased tensile shear and hardness significantly and prolonged lifetime of spot welded joint.

Matched MeSH terms: Hardness; Hardness Tests
Experimental data for effect of carbon black loading on tensile, hardness and rebound of magnetic iron filled natural rubber composites

Ismail R

Data Brief, 2019 Aug;25:104166.
PMID: 31516921 DOI: 10.1016/j.dib.2019.104166

Generally, a base isolator is made up of alternate layers of steel and rubber. The idea of adopting magnetoreological elastomers (MREs) in base isolator systems was introduced in the past few years in order to improve the efficiency of base isolator systems. The article provides information on the mechanical corresponding to different carbon black loading loadings of 20 parts per hundred rubber (pphr), 40 pphr and 60 pphr in natural rubber compound. The mechanical dataset described the data from tensile, hardness and rebound test.

Matched MeSH terms: Hardness
Fulltext Enhancement of mechanical and corrosion resistance properties of electrodeposited Ni-P-TiC composite coatings

Fayyaz O, Khan A, Shakoor RA, Hasan A, Yusuf MM, Montemor MF, et al.

Sci Rep, 2021 Mar 05;11(1):5327.
PMID: 33674680 DOI: 10.1038/s41598-021-84716-6

In the present study, the effect of concentration of titanium carbide (TiC) particles on the structural, mechanical, and electrochemical properties of Ni-P composite coatings was investigated. Various amounts of TiC particles (0, 0.5, 1.0, 1.5, and 2.0 g L-1) were co-electrodeposited in the Ni-P matrix under optimized conditions and then characterized by employing various techniques. The structural analysis of prepared coatings indicates uniform, compact, and nodular structured coatings without any noticeable defects. Vickers microhardness and nanoindentation results demonstrate the increase in the hardness with an increasing amount of TiC particles attaining its terminal value (593HV100) at the concentration of 1.5 g L-1. Further increase in the concentration of TiC particles results in a decrease in hardness, which can be ascribed to their accumulation in the Ni-P matrix. The electrochemical results indicate the improvement in corrosion protection efficiency of coatings with an increasing amount of TiC particles reaching to ~ 92% at 2.0 g L-1, which can be ascribed to a reduction in the active area of the Ni-P matrix by the presence of inactive ceramic particles. The favorable structural, mechanical, and corrosion protection characteristics of Ni-P-TiC composite coatings suggest their potential applications in many industrial applications.

Matched MeSH terms: Hardness
Fulltext New recursive circular algorithm for listing all permutations

Sharmila Karim, Zurni Omar, Haslinda Ibrahim, Khairil Iskandar Othman, Mohamed Suleiman

Pertanika Journal of Science & Technology, 2014;22(1):25-33.
MyJurnal

Linear array of permutations is hard to be factorised. However, by using a starter set, the process of listing the permutations becomes easy. Once the starter sets are obtained, the circular and reverse of circular operations are easily employed to produce distinct permutations from each starter set. However, a problem arises when the equivalence starter sets generate similar permutations and, therefore, willneed to be discarded. In this paper, a new recursive strategy is proposed to generate starter sets that will not incur equivalence by circular operation. Computational advantages are presented that compare the results obtained by the new algorithm with those obtained using two other existing methods. The result indicates that the new algorithm is faster than the other two in time execution.

Matched MeSH terms: Hardness
Fulltext Groundwater from fractured granite and metasedimentary rocks in the west coast of Peninsular Malaysia

Nasiman Sapari, Raja Zainariah Raja Azie, Hisyam Jusoh

Pertanika Journal of Science & Technology, 2012;20(2):371-379.
MyJurnal

Hard rock formations consisting of granite and metasedimentary rocks in Peninsular Malaysia, have beenconsidered to be of poor aquifers. The map of shows the area underlain by hard rock as having poorto moderate potential for groundwater production (

Matched MeSH terms: Hardness
Fulltext Effect of speed and braking load on the wear phenomena of motorcycle

Dafit Feriyanto, Leman, A.M., Achmad Zainuri, Okariawan, I.D.K.

Journal of Occupational Safety and Health, 2015;12(2):49-56.
MyJurnal

In the development of current vehicle capabilities required an effective braking system, has a little wear, and
safety riding. The objective of the research is to determine wear and braking distance because of braking load and
speed motorcycle Honda supra X125 cc. This research used the speed of 50 km/h, 60 km/h, and 70 km/h. Braking load
used to be 4 kg, 5 kg, and 6 kg. The test was done by dynamic method and the research was done in two stages; testing
in the field and measuring brake wear in the lab using a profile projector. Testing the hardness of brake was done to
know hardness brake before and after testing due to the effect of wear, braking time, and braking distance.From testing
it was found that increasing of braking load, resulted in increasing wear. The smallest wear was 6 x 10-5 mm/sea at a
speed of 50 km/h, braking load of 4 kg, and braking time of 15.94 seconds. Increasing the speed resulted in increasing
braking distances with the smallest of braking distance was 55 meters at the breaking load of 6 kg, the speed of 50
km/h and braking time 9.93 seconds. The hardness of brake lining, increased after the brake lining wear testing. The
hardness before the test was 95.8 HRN and after the test was 100.4 HRN.

Matched MeSH terms: Hardness
Fulltext A study of microstructure and hardness on Fe-Co/SiC composites

Noraziana Parimin, Linus, Andy

Journal of Nuclear and Related Technologies, 2009;2009(1):65-70.
MyJurnal

This research was conducted to study the effect of reinforcement particles on iron-cobalt (FeCo) composites. The composition of silicon carbide (SiC) was varied from 0 to 20 wt%. The composite was fabricated via powder metallurgy (PM) method, which consists of mixing, compaction and sintering processes. The powder was mixed for 2 hours to obtain uniformity between SiC and Fe-Co matrix and compacted to a cylindrical shape at 250 MPa. Samples were sintered for 2 hours at 900 o C with 10 o C/minute heating rate in argon atmosphere. The influences of reinforcement particle on the sintered samples were characterized in terms of microstructure and hardness testing. The Fe-Co/20wt%SiC composites show highest hardness value.

Matched MeSH terms: Hardness; Hardness Tests
Fulltext Physicochemical properties and sensory characteristics of sausage formulated with surimi powder

Santana P, Huda N, Yang TA

J Food Sci Technol, 2015 Mar;52(3):1507-15.
PMID: 25745219 DOI: 10.1007/s13197-013-1145-1

The objectives of this study were to determine the physicochemical properties and sensory characteristics of fish sausage made with 100 % threadfin bream (Nemipterus japonicus) surimi powder (SP100), a mix of 50 % surimi powder and 50 % frozen surimi (SP50), and a control (100 % frozen surimi). No significant differences in protein content and folding test results (P > 0.05) were detected among the SP100 and SP50 samples and the control. Gel strength of SP100 was lower (P > 0.05) than that of the control. The texture profile analysis (TPA) values (hardness, cohesiveness, springiness, and chewiness) of SP100 were significantly lower (P

Matched MeSH terms: Hardness
Fulltext Robust foreground detection: a fusion of masked grey world, probabilistic gradient information and extended conditional random field approach

Zulkifley MA, Moran B, Rawlinson D

Sensors (Basel), 2012;12(5):5623-49.
PMID: 22778605 DOI: 10.3390/s120505623

Foreground detection has been used extensively in many applications such as people counting, traffic monitoring and face recognition. However, most of the existing detectors can only work under limited conditions. This happens because of the inability of the detector to distinguish foreground and background pixels, especially in complex situations. Our aim is to improve the robustness of foreground detection under sudden and gradual illumination change, colour similarity issue, moving background and shadow noise. Since it is hard to achieve robustness using a single model, we have combined several methods into an integrated system. The masked grey world algorithm is introduced to handle sudden illumination change. Colour co-occurrence modelling is then fused with the probabilistic edge-based background modelling. Colour co-occurrence modelling is good in filtering moving background and robust to gradual illumination change, while an edge-based modelling is used for solving a colour similarity problem. Finally, an extended conditional random field approach is used to filter out shadow and afterimage noise. Simulation results show that our algorithm performs better compared to the existing methods, which makes it suitable for higher-level applications.

Matched MeSH terms: Hardness
The effects of long-term VDT usage on the nature and incidence of asthenopic symptoms

Yeow PT, Taylor SP

Appl Ergon, 1990 Dec;21(4):285-93.
PMID: 15676784

An opportunity arose in 1985 to become involved in a transition of working practice from hard copy to VDT. Over a two-year period, 161 VDT users and 65 control subjects in the same office environment were regularly and routinely examined for symptoms of asthenopia. The analysis of data shows that there are no significant differences in type, number and frequency of the work-related symptoms between VDT users and non-VDT users. It appears that reporting of symptoms within the group may be random, although certain symptoms do appear more frequently than others. Additionally, it appears that there is a significant difference between male and female users in the frequency of symptom reporting.

Matched MeSH terms: Hardness
Influence of Weather on Hardness and Surface Roughness of Maxillofacial Elastomeric Materials

Mousa MA

J Contemp Dent Pract, 2020 Jun 01;21(6):678-682.
PMID: 33025938

AIMS: The purpose of this study was to assess the influence of hot and dry weather on the hardness and surface roughness of four different maxillofacial silicone elastomeric materials (MFSEM) including two room-temperature vulcanized (RTV) and two high-temperature vulcanized (HTV) materials.
MATERIALS AND METHODS: Eighty test specimens were fabricated according to the manufacturer's instructions into rectangular test specimens. The hardness and surface roughness were tested, after 6 months of exposure to natural hot and dry weather. The hardness was measured through the International Rubber Hardness Degree (IRHD) scale using an automated hardness tester. The surface roughness was measured using a novel 3D optical noncontact technique using a combination of a light sectioning microscope and a computer vision system. Statistical Package for Social Sciences software SPSS/version 24 was used for analysis and a comparison between two independent variables was done using an independent t test, while more than two variables were analyzed, F test (ANOVA) to be used followed by a post hoc test to determine the level of significance between every two groups.
RESULTS: The hot and dry weather statistically influenced the hardness and surface roughness of MFSEM. Cosmesil M-511 showed the least hardness in test groups while A-2000 showed the hardest material (p < 0.05). A-2000 showed significant changes from rough in case of nonweathered to become smoother in weather followed by A-2186 (p < 0.05). Cosmesil M-511 showed the roughest material.
CONCLUSION: Cosmesil M-511 showed the least hard MFSEM after outdoor weathering while A-2000, the highest and least material showed hardness and surface roughness, respectively.
CLINICAL IMPLICATION: A-2000 had a high IRHD scale hardness. This makes this material more suitable for the replacement of ear and nose defects. Cosmesil M-511 is soft and easily adaptable material that makes the material more appropriate for the replacement of small facial defect with undercut area to be easily inserted and removed. Whilst A-2000 is smoother and finer in test specimens after weathering, Cosmesil M-511 became rougher after weathering.

Matched MeSH terms: Hardness
Fulltext Antioxidative and Quality Properties of Full-Fat Date Seeds Brew as Influenced by the Roasting Conditions

Fikry M, Yusof YA, M Al-Awaadh A, Abdul Rahman R, Chin NL, Ghazali HM

Antioxidants (Basel), 2019 Jul 18;8(7).
PMID: 31323854 DOI: 10.3390/antiox8070226

Full-fat roasted date seeds are considered an excellent source of antioxidants which can treat many diseases. The specific objectives were to investigate the effect of roasting temperature and time on the hardness of whole seeds, moisture content of the roasted date seeds powder, DPPH radical scavenging activity, total phenolic contents, extraction yield, pH, browning index and sensory properties of the brew prepared from the full-fat roasted date seeds and to construct descriptive models that could describe this effect. Date seeds were roasted at three temperatures (160, 180 and 200 °C) for different period of times (10, 20 and 30 min) using a natural conventional oven; then grinded and next brewed. Hardness of whole seeds, moisture content of the seeds powder, DPPH radical scavenging activity and total phenolic contents, extraction yield, pH and browning index and sensory properties of the brew were significantly affected by the roasting conditions. The statistical results indicated that the proposed model could adequately describe the measured properties. Strong correlations have been found among the properties of the brew as well. The producers of the date seeds brew can utilize these results for controlling the roasting process.

Matched MeSH terms: Hardness
Fulltext Effect of MgO Addition on the Mechanical and Dynamic Properties of Zirconia Toughened Alumina (ZTA) Ceramics

Arab A, Sktani ZDI, Zhou Q, Ahmad ZA, Chen P

Materials (Basel), 2019 Jul 31;12(15).
PMID: 31370216 DOI: 10.3390/ma12152440

Zirconia toughened alumina (ZTA) is a promising advanced ceramic material for a wide range of applications that are subjected to dynamic loading. Therefore, the investigation of dynamic compressive strength, fracture toughness and hardness is essential for ZTA ceramics. However, the relationship between these mechanical properties in ZTA has not yet been established. An example of this relationship is demonstrated using ZTA samples added with MgO prepared through conventional sintering. The microstructure and mechanical properties of ZTA composites were characterized. The hardness of ZTA composites increased for ≤0.7 wt.% MgO due to the pinning effect of MgO and decrease of the porosity in the microstructure. Oppositely, the fracture toughness of ZTA composites continuously decreased due to the size reduction of Al2O3 grains. This is the main reason of deteriorate of dynamic compressive strength more than 0.2 wt.% of MgO addition. Therefore, the SHPB test shows the improvement of the dynamic compressive strength only up to a tiny amount (0.2 wt.% of MgO addition) into ZTA ceramics.

Matched MeSH terms: Hardness
High mechanical strength and broad optical absorption in underexplored group IV nitride chalcogenides

Chang YHR

Chem Commun (Camb), 2020 Sep 17;56(74):10962-10965.
PMID: 32789397 DOI: 10.1039/d0cc04123h

While lab-scale synthesis of trigonal-Zr2N2S, hexagonal-Zr2N2S and hexagonal-Zr2N2Se has been reported, meaningful data on the photophysical properties of IV-nitride chalcogenides in general are scarcely available. The first-principles calculations and genetic algorithm modeling in our work reveal the existence of remarkably stable, indirect gap trigonal-Zr2N2Se and trigonal-Hf2N2Se phases, which progress to direct gap, monoclinic materials in monolayer form. These structures display the desired optoelectronic properties, such as exceptionally high visible-UV absorption spectra (105-106 cm-1) and exciton binding energy below 0.02 eV. Strong hybridization between the Zr-d, N-p and Se-p orbitals is accounted for by the polysilicon comparable Vickers hardness (10.64-12.77 GPa), while retaining ductile nature.

Matched MeSH terms: Hardness
Fulltext Evaluation on Soil Hardness in Riparian Forest Restoration along Kayan Ulu River, Sarawak, Malaysia

AINA NADIA NAJWA MOHAMD JAFFAR, MOHD EFFENDI WASLI, MUGUNTHAN PERUMAL

Trends in Undergraduate Research, 2018;1(1):0-0.
MyJurnal

Soil hardness plays a vital role in evaluating the physical properties of soil structure. With regards to the impact of compaction on practical forest management issues, most report and review forms were available. Thus, the aim of this study was to evaluate the soil condition in riparian forest restoration planted with indigenous species along Kayan Ulu River with special reference to soil hardness. Soil hardness was measured by using Hasegawa-type cone penetrometer from the surface soils to 100 cm depth, with a total of 48 random points for both study sites surveyed; restoration sites planted with Shorea macrophylla in year 1996 and 1998 (SPD96 and SPD98, respectively) for both on and between planting lines. Our findings indicated that, soil hardness in SPD98 was harder as compared to SPD96 at shallow depth presented in one drop penetrability. Likewise, soil penetration resistance on planting line in SPD98 was significantly higher than SPD96 at surface soils (0-20 cm) and subsurface soils (20-40 cm). A high number of strikes and soil penetration resistance indicate that the soils were highly compacted. However, there was no significant difference in term of soil penetration resistance between planting line. In order to avoid effects on tree productivity, it is recommended that in future, the evaluation of soil hardness should be determined during the early establishment for future restoration of riparian ecosystem.

Matched MeSH terms: Hardness
Fulltext New Experimental Zirconia-Reinforced Rice Husk Nanohybrid Composite and the Outcome of Its Surface Roughness and Microhardness in Comparison with Commercialized Nanofilled and Microhybrid Composite Resins

Lin GSS, Ghani NRNA, Ismail NH, Singbal K, Noorani TY, Mamat N

Contemp Clin Dent, 2021 03 20;12(1):21-27.
PMID: 33967533 DOI: 10.4103/ccd.ccd_298_20

Background: An ideal composite resin should demonstrate smooth surface after polishing and high hardness value to provide long-term success. Thus, this study aimed to compare the surface roughness and microhardness of new experimental zirconia-reinforced rice husk nanohybrid composite (Zr-Hybrid) with commercialized nanofilled (Filtek-Z350-XT) and microhybrid composite (Zmack-Comp) resins before and after artificial ageing.
Methods: One hundred and eighty standardized disc samples were prepared, of which ninety samples each were used for surface roughness and microhardness test, respectively. They were divided equally into: Group 1 (Filtek-Z350-XT), Group 2 (Zmack-Comp), and Group 3 (Zr-Hybrid). For surface roughness test, all samples were polished with aluminium oxide discs and further subdivided into aged and unaged subgroups, in which composite samples in aged subgroups were subjected to 2500 thermal cycles. Next, all the samples were subjected to surface roughness test using a contact stylus profilometer. As for microhardness test, all the aged and unaged samples were tested using a Vickers hardness machine with a load of 300 kgf for 10 s and viewed under a digital microscope to obtain microhardness value. Data were analyzed using two-way ANOVA followed by post hoc Tukey's honestly significant difference and paired sample t-test with significance level set at P = 0.05.
Results: In both the aged and unaged groups, Zr-Hybrid showed statistically significantly lower surface roughness (P < 0.05) than Filtek-Z350-XT and Zmack-Comp, but no statistically significant difference was noted between Filtek-Z350-XT and Zmack-Comp (P > 0.05). A similar pattern was noted in microhardness test, whereby Zr-Hybrid showed the highest value (P < 0.05) followed by Filtek-Z350-XT and lastly Zmack-Comp. Besides, significant differences in surface roughness and microhardness were noted between the aged and unaged groups.
Conclusion: Zr-Hybrid seems to demonstrate better surface roughness and microhardness value before and after artificial ageing.

Matched MeSH terms: Hardness
Quality characteristics of Malaysian commercial beef frankfurters

Nurul, H., Alistair, T.L.J., Lim, H.W., Noryati, I.

International Food Research Journal, 2010;17(2):469-476.
MyJurnal

Five different brands of Malaysian commercial beef frankfurters were analyzed for quality characteristics. The proximate contents showed significant differences among the samples. The range of moisture content was 63.0-73.9%; the protein content was 10.63-16.43% while the fat content was 1.71-12.22%. The lightness value (L*) of the uncooked frankfurters, which was in the range of 47.02-52.28, was significantly different among the samples. The lightness of the cooked frankfurters, showed a decrease in all the samples compared to the uncooked samples. No significant differences were observed for the folding test; where all samples showed no cracks after they were folded in half. However, significant differences were observed for the texture analysis. The hardness, cohesiveness, chewiness, springiness, gumminess and shear force ranged between 4.59-10.30 kg, 0.26-0.35, 16.15-51.72 kgmm, 12.73-14.79 mm, 1.17-3.49 kg and 1.67-7.08 kg respectively. The results of the study showed that Malaysian commercial beef frankfurters were significantly different in their physicochemical properties.

Matched MeSH terms: Hardness
Fulltext Textural and sensorial properties of cookies prepared by partial substitution of wheat flour with unripe banana (Musa x paradisiaca var. Tanduk and Musa acuminata var. Emas) flour

Norhidayah, M., Noorlaila, A., Nur Fatin Izzati, A.

International Food Research Journal, 2014;21(6):2133-2139.
MyJurnal

The textural and sensorial properties of the cookies prepared by partial substitution of wheat flour with two types of unripe banana flour (UBF) were studied. The green matured unripe banana (Musa x paradisiaca var. Tanduk and Musa acuminata var. Emas) was used to partially substitute the usage of wheat flour at 0% (control), 25% and 50% level in the formulated plain cookies. Textural (hardness) and sensorial properties were conducted on all samples. Substitution of UBF to formulation of cookies had increased the hardness of cookies (ranging from 967 N to 1665 N) compared to the control except for substitution of Emas banana flour (EBF) at 50% which was not significantly difference (p > 0.05) with control sample. The substitution of 25% of Tanduk banana flour (TBF) showed the highest mean score in overall acceptability (6.81 ± 1.18) compared to all treated samples. TBF substitution is feasible up to 50% substitution while for EBF, the substitution only up to 25% level in this study.

Matched MeSH terms: Hardness

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