Development of a mini-tribometer for in-situ observation of subsurface and the corresponding experiments

Purpose This paper aims to develop a Mini-Tribometer for in-situ observation of subsurface. Design/methodology/approach To observe the change of the microstructure during wear in real time, an in-situ observation mini-tribometer was developed according to the requirements of the basic frictional experiments and carried out the verification experiments. Findings The subsurface images and the tribological data obtained from the mini-tribometer clearly show that the graphite in the matrix moves to the surface and takes part in lubrication mainly in the form of extrusion and peeling off, and the migration of graphite in the copper-based composite to the frictional interface to act as lubricant and to result in the decrease of the friction coefficient. The experimental results of the developed tribometer are accurate, which can provide important references for further research on the wear mechanism of materials. Originality/value The developed in-situ observation mini-tribometer can be used to observe the dynamic wear mechanism of the frictional pairs, which is very important for optimization of material design and tribological performances.

BANTUAN TEKNIS PELAKSANAAN PENGECATAN BALAI RW XI JALAN SILIKAT KELURAHAN PURWANTORO KECAMATAN BLIMBING KOTAMADYA MALANG

Balai RW is a construction or building used by residents for RT activities or activities of local residents and has been built since 1998 and is used as a place for local residents' activities. For the condition of the Balai RW XI in 2020 today, there are many that are not suitable for use, especially in wall construction, where many conditions are damp and the wall paint is peeling off so that repairs are needed in the form of painting the outer and inner walls. Implementation of Community Service Painting of Balai RW XI Jl. Silikat Kel.. Purwantoro Kec. Blimbing Malang city is carried out are: 1. Calculation of the Budget Plan for Painting Implementation Costs Balai RW XI is Rp. 13,955,000, - (Thirteen Million Nine Hundred Fifty Five Thousand Rupiah) the source of funds from PKM Polinema activities and RW XI Cash. 2. Painting the Balai RW XI is prioritized on repairing inner and outer wall paints. 3. Implementation of painting at Balai RW XI will be carried out from 20 July 2020 - 8 August 2020 with a total processing time of 3 weeks.

Detection DETEKSI DAN IDENTIFIKASI KAPANG PADA PROSES BIODETERIORASI ARSIP FOTO MEMORY OF THE WORLD (MOW) RESTORASI CANDI BOROBUDUR

ABSTRACT This study aims to identify the genus of mold in the biodeterioration process of the photo archive of Memory of the World (MoW) restoration of Borobudur Temple and the potential for the enzymatic activity of these molds. The type of research method chosen is descriptive qualitative. Starting with survey sampling and sampling. Inoculation of fungi using the streak method on PDA medium. Mold identification based on macroscopic and microscopic observations of fungi. The results of characterization were then identified using the matching profile method using the mold identification reference book. The identification results resulted in six genera of contaminant molds in the biodeterioration of the MoW photo archive of the Borobudur Temple restoration. The genera identified included: Acremonium (69.66 %%), Penicillium (14.59%), Aspergillus (3.36%), Culvularia (2.24%) Fusarium (1.12%), and Pleurostomophora (1.12%) and some sterile mycelia. The types of biodeterioration in the photo collection include mold growth, discolored spots, peeling off layers, and damage to the substrate in the photo. Based on literature search, all mold genera found as the cause of biodeterioration has the potential to have proteinase, gelatinase, and cellulase enzymes. Keywords: Biodeterioration; Mold; Photograph; Memory of the World; Borobudur Temple

Deterioration of modern concrete structures and asphalt pavements by respiratory action and trace quantities of organic matter

In concrete structures (concrete), damage from cracks, deterioration, amorphization, and delamination occur in some structures, causing disaggregation (concrete changed to very fine particles) and hollowing out of the concrete. In concrete pavements, damage from large amounts of pop-out of aggregate occurs from the surface of the concrete pavement 4–5 hours after spraying of snow melting agent on the surface of the pavement. The damage from disaggregation, blistering, cracks, and peeling-off of a surface course have also been observed in asphalt runways and highways. The damage from disaggregation, cracks and pop-out of aggregate in asphalt pavements and concrete structures have long been seen as strange and unexpected and have defied explanation. As a result of examinations in various experiments, it was concluded that all of the unexplained kinds of damage of both asphalt pavements and concrete structures were caused by Trace Quantities of Organic Matter (TQOM), Air Entrained (AE) water reducing agent in air and/or cement, and surfactant in snow melting agent. The emission sources of TQOM and these organic substances were also identified by chemical analysis for these unexpected and unexplained phenomena. The TQOM includes phthalate compounds (phthalates in the following), amine compounds, phosphate compounds, snow melting agent and Sodium Polyoxyethylene Nonyl phenyl Ether Sulfate (SPNES). SPNES is a surfactant in windshield washer fluid for automobiles. We found that the water content and content of organic matter in damaged asphalt pavements and concrete structures are also important indicators for the damage. Further, a new evaluation method for amorphization was proposed in this study and it appears suitable for evaluating the safety of concrete structures along roads which were exposed to TQOM in severely air-polluted environments.

Lithospheric structure beneath southern Iberia and northern Morocco constrained by 3D Kirchhoff-approximate GRT imaging

The slab beneath the Alboran Sea is a consequence of the collision between two continents (Europe and Africa), which was initiated along the northeastern Spanish coast, experienced slab rollback and migrated to the area adjacent to the two continents. The tectonic background in this area includes episodes of collisions with adjacent continents as well as extension of those basins in the western Mediterranean. Here, we present three-dimensional (3D) Kirchhoff-approximate generalized Radon transform (GRT) images to further constrain the lithospheric structures previously identified by other researchers. The GRT images were calculated from the same P-to-S (Pds or Ps) teleseismic receiver functions (RFs) as the previous common conversion point (CCP) stacking, but the GRT data provide figures with greater resolution than the Pds RFs CCP results. This study indicates that the Alboran Slab may have completely detached from the crustal base under the western Betics Mountains and that a larger range of lithospheric ‘peeling off’ developed beneath the western part of the Betics Mountains than some previous results have claimed. The observed thin lithosphere under the Middle Atlas (MA) and eastern High Atlas (HA) may have a geodynamic relationship with lithospheric delamination under the eastern part of the Rif Mountains, which has also led to the thin lithosphere under the eastern Rif. According to the thick lithosphere under the western HA, the shallow LAB under the MA and eastern HA may have no heat-flow connection with the Canary mantle plume, as stated in several previous studies.

Peeling off foregrounds with the constrained moment ILC method to unveil primordial CMB B modes

ABSTRACT Galactic foregrounds are the main obstacle to observations of the cosmic microwave background (CMB) B-mode polarization. In addition to obscuring the inflationary B-mode signal by several orders of magnitude, Galactic foregrounds have non-trivial spectral signatures that are partially unknown and distorted by averaging effects along the line of sight, within the pixel/beam window, and by various analysis choices (e.g. spherical harmonic transforms and filters). Statistical moment expansion methods provide a powerful tool for modelling the effective Galactic foreground emission resulting from these averaging effects in CMB observations, while blind component separation treatments can handle unknown foregrounds. In this work, we combine these two approaches to develop a new semiblind component separation method at the intersection of parametric and blind methods, called constrained moment ILC (cMILC). This method adds several constraints to the standard ILC method to deproject the main statistical moments of the Galactic foreground emission. Applications to maps are performed in needlet space and when compared to the NILC method, this helps in significantly reducing residual foreground contamination (bias, variance, and skewness) in the reconstructed CMB B-mode map, power spectrum, and tensor-to-scalar ratio. We consider sky simulations for experimental settings similar to those of LiteBIRD and PICO, illustrating which trade-offs between residual foreground biases and degradation of the constraint on r can be expected within the new cMILC framework. We also outline several directions that require more work in preparation for the coming analysis challenges.

Tribological Behavior of Phenolic Resin-Based Friction Composites Filled with Graphite

In this paper, the influence of graphite (Gr) on the dry sliding tribological properties of phenolic resin (PF) composites was studied under different sliding speeds of 3.1–47.1 m/s. The wear mechanism was investigated by the observation of the morphology of the transfer layer during the dry sliding process. It was found that the addition of Gr could decrease the friction coefficient and wear rate effectively, and the friction coefficient and wear rate decreased with the increase of Gr content in the range of 10–30 vol.%. The dominant wear mechanisms of PF-based friction composites changed from adhesive wear to fatigue wear (in the form of peeling-off) in the high sliding speed condition after the addition of Gr. The addition of Gr effectively reduced the sensitivity of PF-based friction materials to sliding speeds, and thus enhanced the stability of the friction coefficient. When the content of Gr was above 20 vol.%, the stability of the friction coefficient was relatively steady.