The Mars system revealed by the Martian Moons eXploration mission

Japan Aerospace Exploration Agency (JAXA) plans a Phobos sample return mission (MMX: Martian Moons eXploration). In this study, we review the related works on the past climate of Mars, its evolution, and the present climate and weather to describe the scientific goals and strategies of the MMX mission regarding the evolution of the Martian surface environment. The MMX spacecraft will retrieve and return a sample of Phobos regolith back to Earth in 2029. Mars ejecta are expected to be accumulated on the surface of Phobos without being much shocked. Samples from Phobos probably contain all types of Martian rock from sedimentary to igneous covering all geological eras if ejecta from Mars could be accumulated on the Phobos surface. Therefore, the history of the surface environment of Mars can be restored by analyzing the returned samples. Remote sensing of the Martian atmosphere and monitoring ions escaping to space while the spacecraft is orbiting Mars in the equatorial orbit are also planned. The camera with multi-wavelength filters and the infrared spectrometer onboard the spacecraft can monitor rapid transport processes of water vapor, dust, ice clouds, and other species, which could not be traced by the previous satellites on the sun-synchronous polar orbit. Such time-resolved pictures of the atmospheric phenomena should be an important clue to understand both the processes of water exchange between the surface/underground reservoirs and the atmosphere and the drivers of efficient material transport to the upper atmosphere. The mass spectrometer with unprecedented mass resolution can observe ions escaping to space and monitor the atmospheric escape which has made the past Mars to evolve towards the cold and dry surface environment we know today. Together with the above two instruments, it can potentially reveal what kinds of atmospheric events can transport tracers (e.g., H2O) upward and enhance the atmospheric escape. Graphical Abstract

Environmental Impact of C Excavation Mining Activities in Banyakan District

C Excavation mining activity in Banyakan District, Kediri Regency has been going on for a long time. It is needed to support the creation of good infrastructure and become one of the foundations for development progress, but in its implementation it must pay attention to the preservation of the natural environment. This study uses descriptive analysis method with a quantitative approach, and uses survey and interview methods for data collection. Afterward, the survey data were analyzed by non-parametric test using the free K-sample test, validity and reliability tests, and quantitative analysis using the Analytical Hierarchy Process (AHP) method. Thereafter, with expert recommendations, a strategy for managing the impact was developed. The results of the discussion found that environmental damage due to C excavation activities that often occur and has a major impact in Tiron Village, Banyakan District, includes damage to road infrastructure, air pollution due to material transport vehicle traffic, and loss of rural feel. Therefore, all parties must work together to overcome this, several responses that can be taken to deal with these impacts include all parties having to allocate special funds for road infrastructure improvements, policies from the government that are in favor of the community and the environment, and reclamation of mining former lands to restore a rural feel and good air quality standards

Self-consistent modeling of MBE self-catalyzed GaAs nanowire growth

Self-catalyzed GaAs nanowires are synthesized by molecular beam epitaxy at various arsenic fluxes and growth temperatures. The growth of GaAs nanowires is simulated considering the kinetics of material transport inside the catalyst droplet. The re-evaporation coefficient of arsenic is estimated for the given growth conditions. Calculated nanowire growth rate is in satisfactory agreement with the experimental data.

The effect of anion architecture on the lubrication chemistry of phosphonium orthoborate ionic liquids

Phosphonium ionic liquids with orthoborate anions have been studied in terms of their interfacial film formation, both physisorbed and sacrificial from chemical breakdown, in sheared contacts of varying harshness. The halogen-free anion architecture was varied through (i) the heteronuclear ring size, (ii) the hybridisation of the constituent atoms, and (iii) the addition of aryl functionalities. Time of Flight-Secondary Ion Mass Spectrometry analysis revealed the extent of sacrificial tribofilm formation allowing the relative stability of the ionic liquids under tribological conditions to be determined and their breakdown mechanisms to be compared to simple thermal decomposition. Overall, ionic liquids outperformed reference oils as lubricants; in some cases, sacrificial films were formed (with anion breakdown a necessary precursor to phosphonium cation decomposition) while in other cases, a protective, self-assembly lubricant layer or hybrid film was formed. The salicylate-based anion was the most chemically stable and decomposed only slightly even under the harshest conditions. It was further found that surface topography influenced the degree of breakdown through enhanced material transport and replenishment. This work thus unveils the relationship between ionic liquid composition and structure, and the ensuing inter- and intra-molecular interactions and chemical stability, and demonstrates the intrinsic tuneability of an ionic liquid lubrication technology.

In situ science on Phobos with the Raman spectrometer for MMX (RAX): preliminary design and feasibility of Raman measurements

Mineralogy is the key to understanding the origin of Phobos and its position in the evolution of the Solar System. In situ Raman spectroscopy on Phobos is an important tool to achieve the scientific objectives of the Martian Moons eXploration (MMX) mission, and maximize the scientific merit of the sample return by characterizing the mineral composition and heterogeneity of the surface of Phobos. Conducting in situ Raman spectroscopy in the harsh environment of Phobos requires a very sensitive, compact, lightweight, and robust instrument that can be carried by the compact MMX rover. In this context, the Raman spectrometer for MMX (i.e., RAX) is currently under development via international collaboration between teams from Japan, Germany, and Spain. To demonstrate the capability of a compact Raman system such as RAX, we built an instrument that reproduces the optical performance of the flight model using commercial off-the-shelf parts. Using this performance model, we measured mineral samples relevant to Phobos and Mars, such as anhydrous silicates, carbonates, and hydrous minerals. Our measurements indicate that such minerals can be accurately identified using a RAX-like Raman spectrometer. We demonstrated a spectral resolution of approximately 10 cm−1, high enough to resolve the strongest olivine Raman bands at ~ 820 and ~ 850 cm−1, with highly sensitive Raman peak measurements (e.g., signal-to-noise ratios up to 100). These results strongly suggest that the RAX instrument will be capable of determining the minerals expected on the surface of Phobos, adding valuable information to address the question of the moon’s origin, heterogeneity, and circum-Mars material transport. Graphical Abstract

The Effect of Material Conveyances on Workload, Musculoskeletal Disorders, Productivity and Performance in the Process of Plate Cutting

The use of material conveyances that are not in accordance with the concept of ergonomics harm the human body. Repair of work brushes by applying ergonomics to material conveyances can reduce the risk category. The purpose of this study was to determine the effect of material conveyance on reducing workload, musculoskeletal disorders, increasing productivity and performance. The study was conducted using the same subject design method with a sample of 16 workers. The data were analyzed by paired t-test with a significant level of p<0.05. The results of the analysis showed that the PO workload data was 104.4 beats per minute, P1 was 93.5 beats per minute there was a decrease of 10.9 beats per minute or 10.4%, PO musculoskeletal complaints were 80.1 scores, P1 was 70.0 the scores were decreased by 10.1 or 12.6%, PO productivity of 0.201, P1 of 0.355, an increase of 0.154 or 43.4%. The conclusion is that the use of material conveyances means a decrease in workload, musculoskeletal disorders, an increase in productivity and performance. It is recommended to workers to use material conveyances equipment in carrying out transport and material transport activities.

A Driver and Control Method for Primary Stator Discontinuous Segmented-PMLSM

In recent years, with the development of the permanent magnet linear synchronous motor (PMLSM), the application of PMLSM has not been limited only to the high-end equipment field; the primary stator discontinuous segmented-PMLSM (DSPMLSM), which consists of multiple primary stators and one mover, has also been applied in long-distance transportation systems, such as electromagnetic launch, high precision material transport, etc. Compared with the symmetry phase parameters of conventional PMLSM, the stationary electrical parameters vary when the mover enters and leaves the primary stators (the inter-segment region). At the same time, due to the sectional power supply, there will be primary suction or pulling force when the mover enters and exits the inter-segment region, which will lead to large thrust fluctuation and result in lager position error. This paper proposed a related drive and control strategy about the DSPMLSM system, which improved the position tracking accuracy during the full range of DSPMLSM. First, the parameter variation between stator segments has been analyzed through finite element simulation of DSPMLSM. Then, a double closed-loop series control structure of position-current is designed, in which a PI-Lead controller was adopted for the position loop and a PI controller was adopted for the current loop. In order to improve the position tracking accuracy of DSPMLSM, a thrust fluctuation extended state observer (TFESO) was adopted to observe and compensate the complex thrust disturbances such as cogging force, friction and other unmodeled thrust fluctuation. At last, the DSPMLSM experimental stage was established, and the experimental results show that the proposed driver and control theory can effectively improve the position tracking accuracy of the whole stroke of DSPMLSM.

Effect of interface-active proteins on the salt crystal size in waterborne hybrid materials

Aqueous processes yielding hybrid or composite materials are widespread in natural environments and their control is fundamental for a multiplicity of living organisms. Their design and in vitro engineering require knowledge about the spatiotemporal evolution of the interactions between the involved liquid and solid phases and, especially, the interphases governing the development of adhesion during solidification. The present study illustrates the effects of distinct proteins on the precipitation of sodium chloride encompassing the size, shape and distribution of halite crystals formed during the drying of droplets containing equally concentrated saline protein solutions. The precipitates obtained from aqueous sodium chloride formulations buffered with tris(hydroxymethyl)aminomethane (Tris) contained either bovine serum albumin (BSA), fibrinogen or collagen and were characterized with respect to their structure and composition using optical and electron microscopy as well as x-ray analysis. The acquired findings highlight that depending on the protein type present during droplet drying the halite deposits predominantly exhibit cubic or polycrystalline dendritic structures. Based on the phenomenological findings, it is suggested that the formation of the interphase between the growing salt phase and the highly viscous saline aqueous jelly phase containing protein governs not only the material transport in the liquid but also the material exchange between the solid and liquid phases.