Optimal Area Research Articles

Compartmentalization studies of a deep-design batch Microbial Fuel Cell assembly

Microbial fuel cells (MFCs) are a promising technology in bioelectricity production. Water systems may be utilized in producing electricity by bio-electrochemical catalytic activity of its inherent microbial culture while simultaneously treating wastewater. Current studies are focusing on design and material optimization for future up-scaling application. For large-scale application, optimization studies such as compartmentalization and stacking become important. In this study, a membrane-less microbial fuel cell is designed and optimized in terms of optimum electrode distances and optimum surface area ratios. It was found that the specific design yielded a maximum of 25.81 mV at the optimum distance wherein dissolved oxygen is sufficiently low enough in this level. Through the optimization of electrode distance was also found that the MFC designed is anode-limited with a 1:4 ratio of anode to cathode is required to produce its maximum power density output. Multiple electrodes study proves the MFC setup is stackable even without membrane separation. This paper reports the first known attempt to quantify an optimum surface area to volume ratio at 2.34 m2/m3.

Higher-order aberrations in keratoconus suspect

Purpose: The aim of this study was to assess the pattern of higher-order aberrations (HOAs) in keratoconus suspect (KCS) eyes using Scheimpflug–Placido topography (Sirius, CSO, Italy) and also to detect the sensitivity and specificity of all parameters to discriminate subclinical keratoconus (KC), and normal eye was investigated. Patients and Methods: This was a retrospective, cross-sectional study of 100 eyes of KCS patients along with 50 normal eyes as a control group. The following parameters were evaluated: sphere, cylinder, spherical equivalent, flat and steep keratometry (K), mean K, total root mean square (RMS), RMS coma, RMS spherical aberration, and anterior and posterior corneal elevation in the most curved part of the cornea. All eyes underwent Sirius Scheimpflug–Placido topography evaluation. Results: The KCS group showed significantly higher values for cylinder, mean flat, steep, and mean keratometry (K) compared to the control group. There were statistically significant differences in all aberrometric parameters in KCS compared with the control group except for spherical aberration. The optimum cutoff point and area under receiver operating characteristic curve of both RMS and elevation (anterior and posterior) achieved larger than 90% in both sensitivity and specificity. Conclusion: HOAs and corneal elevation (anterior and posterior) of the most curved part of the cornea proved to be able to distinguish KCS from the normal control group. Higher amounts of vertical coma and larger values of coma-like RMS have been found in patients with suspect KC when compared to normal corneas.

Cooperative Control for Multi-Excitation Units WPT System With Multiple Coupling Parameter Identification and Area Adaptation

In a multiple excitation unit wireless power transfer system, power control flexibility is a critical feature. To develop a system with environmental sensing capability and a smart power distribution strategy, a cooperative control method is proposed for the excitation units. A multiple coupling coefficient identification method was developed by utilizing the DC information of each excitation unit. Furthermore, a bi-operation mode with adaptive area division is proposed to achieve maximum efficiency in the optimum coupling area and to satisfy the fundamental power requirement for a weak coupling area. In the identification and control implementation process, this method is easy to implement and the response speed can be guaranteed because only the DC input current and the duty cycle of the DC regulator information are required. In addition, the proposed approach was evaluated based on experimental analysis.

Examining Human-Autonomy Team Interaction and Explicable Behavior in a Dynamic LEGO Construction Task

Abstract The primary goal of this experiment is to examine and build dynamical systems models which specify the optimum coordination area that enables teams to perform better when they collaborate with an autonomous agent in the context of explicable behavior. In this preliminary study, we examine team coordination dynamics and explicable behavior by using Joint Recurrence Plot (RP) and Joint Recurrence Quantification Analysis (JRQA). In our example, visualizations of the interaction patterns show when explicable behavior happened, notably, during unexpected events, e.g., when there was a missing LEGO brick. Our preliminary data provides some initial findings about team interaction under dynamical changes along with content under uncertainty. Current and future work is focused on additional experimentation with three types of team configurations: all-human, human-agent, and human-multiagent. Through more experimentation, additional insights and examples of other unexpected events will be able to highlight any necessary additional requirements needed for effective teamwork.

Study of the influence of the addition of an exothermic mixture and the ratio of the components of the exothermic mixture on the melting indices at FCAW

An important issue in the processes of strengthening and restoration of surfaces exposed to abrasive, abrasive-corrosive and hydroabrasive wear, using the process of self-protective flux-cored arc welding (FCAW), is to increase the productivity of hardfacing and the quality of the hardfacing metal. The literature review showed that one of the ways to increase the productivity of hardfacing and improve the quality of the hardfaced metal is to add an exothermic mixture to the core filler of flux-cored wire electrode. The effect of composition of filler core during FCAW on the fusion parameters, namely the addition of exothermic mixture (TM), the ratio of exothermic mixture components (CuO/Al), and the ratio of exothermic mixture oxidant to carbon content in the core composition (CuO/C) has been studied. It has been found that the optimum areas for the deposition rate (Gd), deposition factor (ad) and spattering factor (ψs) are observed for the following values of the core components: TM = 25…39, CuO/C = 5…6, CuO/Al = 3…4.

The Experimental Determination of Optimum Parameters of the Equipment for Processing Grain in Preparation for Grinding

Introduction. Modern technology of grain processing pays special attention to the qualitative and efficient preparation of grain for milling. At small enterprises with a reduced technological process, this is almost the only way to improve product yield and quality. Without proper multi-stage preparation of grain for milling at small enterprises, it is impossible to achieve the required quality and quantity of products produced by industrial mills. Grain peeling is one of the most effective ways to clean the surface from dirt and remove outer shells. The removal of outer shells allows increasing the yield of high-grade flour at reduced milling diagrams. The efficiency of the peeling process is significantly infuencet by the design and operating parameters of the peeling machine. The purpose of this work is the experimental determination of optimal conditions for grain processing in the peeling and drying machine (the optimal combination of factors). Materials and Methods. To determine optimal conditions for grain processing in the peeling and drying machine, the method of extreme planning of the experiment was applied. The method of random balance was used to select the most significant factors based on their influence on the optimization parameter. The method of steep ascent on the response surface (the Box – Wilson method) was used to find the optimum area (the planning matrix was realized and statistical analysis of results and steep ascent on the response surface was carried out). Verification of the results was carried out on the software Statistica 10.0. Results. On the basis of experiments, a mathematical model of the technological process of wheat processing in the peeling and drying machine there were obtained, which linked the structural and mode parameters of the machine with the humidity of the treated grain. The results of the experiment confirmed the operability of the developed machine when working with high-humidity grain; they are fundamental for the machine’s further modernization. Discussion and Conclusion The analysis of the controlled factor dispersion diagram allowed us to select the most significant of them based on influence on the selected optimization parameter, the white flour color obtained from the treated grain. As a result of the evaluation of experimental data of the conducted studies, the design and mode parameters of the developed machine were determined, corresponding to the areas of the optimal optimization parameter: shaft rotation speed is 1400 rpm, angle of inclination of stamping on the sieve drum is 15 degrees, the initial moisture content of the processed grain is 15.50%, and the machine productivity does not exceed 700 kg/h.

Design of Minimum Length Supersonic Nozzle using the Method of Characteristics

The work focuses upon design of minimum length supersonic nozzle, using the method of characteristics, for the given combustion chamber conditions, which are going to serve as nozzle inlet conditions. It is assumed that the flow has somehow been accelerated to the sonic value through a suitable convergent nozzle and from that point; the divergent portion of the nozzle is to be designed using the method of characteristics. The optimum exit area and hence, the Mach number are predicted and this Mach number is the value for which the nozzle has to be designed. The results obtained are validated with the results obtained by validation in ANSYS and based on the observation, followed by a discussion on the optimisation of results.

Solar-assisted steam power plant retrofitted with regenerative system using Parabolic Trough Solar Collectors

This work investigates the performance of a conventional steam power plant retrofitted with a solar-assisted regenerative system using Parabolic Trough Solar Collectors (PTC). The solar collectors were used to compensate for the effect of removing Low-Pressure (LP) turbine extractions without changing other elements of a 300 MW power plant unit during peak load operations. The steam power plant, located in Kuwait, receives high levels of solar irradiation. Modeling of the solar-assisted regenerative system using PTC is simulated for Kuwait’s weather conditions. Results of the system analysis show that removing the LP turbine extractions enhanced the performance of the steam power plant by 9.8 MW, with an optimum PTC aperture area equal to 25,850 m2. A techno-economic analysis was used to estimate the Levelized Cost of Energy (LCOE). Compared to an equivalent photovoltaic solar plant, the optimum aperture area and LCOE for the PTC solar plant were found to be less by 45% and 44%, respectively. When compared to an equivalent conventional steam turbine, the solar-assisted steam power plant decreased cost by 56% over the lifecycle of 25-years.

92 Using physical parameters of bovine zygotes to predict invitro development success

The objective of this study was to determine if physical parameters of bovine zygotes are correlated with invitro development success. We examined the relationship between a zygote's outer diameter (OD), cell area, and zona pellucida (ZP) thickness on blastocyst development and blastomere number. Bovine cumulus-oocyte complexes, from abattoir-derived ovaries, were matured in tissue culture medium 199-based maturation medium for 21-23h. Invitro fertilisation was performed with frozen thawed semen containing a pool of 4 Holstein bulls. After incubation with sperm for 16-18h, presumptive zygotes (n=875) were denuded and placed in 5µL droplets of synthetic oviductal fluid-bovine embryo 1 medium (SOF-BE1) under oil to be individually photographed using an inverted scope with a digital camera. Zygotes were then group-cultured in 50µL of synthetic oviductal fluid-BE1 droplets in a polyester micromesh to identify individuals. Development to the blastocyst stage was recorded on Day 7 and Day 8 of culture, and Day 8 embryos were fixed and stained with Hoechst 33342 (n=87). ImageJ was used to measure the OD, area, and ZP from images. Data were analysed with a logistic regression using the lme4 package in R with Day 7 or Day 8 blastocyst development as the response; OD, area, and ZP as predictors; and study replicate (n=11) and culture droplet as random effects. Residual estimates of area and ZP calculated from OD were used to account for collinearity. Average OD was 151.2µm, ranging 130.4-171.6µm. Average ZP was 11.8µm, ranging 7.2-17.5µm. Area averaged 9856.7µm2, ranging from 6421.9 to 13 814.8 µm2. There was a tendency for an effect of OD on probability of development on Day 8 (P=0.08) but not Day 7. There was an effect of ZP on the probability of development on Day 8 (P=0.04) but not Day 7. Blastocyst rates on Day 8 for zygotes with ZP <11.8µm were 24.3%, whereas zygotes with ZP >11.8µm were 21.7%. There was an interaction (P<0.05) between OD and ZP thickness on Day 7 and Day 8. Estimated probability of development of zygotes with ZP <10.7µm and OD <146.9µm averaged 28.5%, whereas those with ZP >12.7µm and OD >155.8µm averaged 43.3%. The observed blastocyst rates for these two groups were 26.2% and 25%, respectively. Zygotes with OD between 146.9-155.8µm and ZP between 10.7-12.7µm had an estimated development probability of 22.2%. The obtained Day 8 blastocyst rate for this group was 22.5%. Area did not affect probability of development, but was positively correlated with total blastomere number at Day 8 (P=0.01; marginal R2=0.09). The observed interaction between ZP thickness and OD may be indicative of an optimum ooplasm area before maturation or fertilisation that may enhance development. Area assessment after fertilisation is not correlated with development success. In addition, these data in comparison with our previous data generated in parthenogenetic embryos indicate that artificial activation of oocytes is not an ideal model in place of IVF for studying development. We continue to demonstrate that physical parameters of zygotes may have potential as a noninvasive, objective selection tool of embryos.

Calculate the optimum slot area of elliptical microstrip antenna for mobile application

<p>Designing and analysis the antenna parameter, for the calculation optimum the slot area for a new broadband elliptical antenna for mobile application, to enhancement impedance bandwidth. Two equations have been obtained, representing the first relationship between the area of the slot and the area of the patch, and the second represents the area of the slot to the wavelength of the band frequency. The antenna was implemented and gets simulation result using CST software and manufacturing on an FR-4 material with =4.3, tan (δ) =0.002 and the feeding line has a characteristic impedance of 50Ω. The proposed antenna is operating in the bandwidth 24GHz and the gain (6.8) dBi.</p>

Monitoring method and test of wheat harvester loss rate based on PVDF sensor

Aiming at the problem that the cleaning loss of wheat harvester affects the harvesting quality, we developed a loss detection system based on PVDF (polyvinylidene fluoride) piezoelectric film cleaning loss sensor. After the study of the relationship between the impact speed and the piezoelectric effect of the scavenging screen, the filtering method for discriminating the grain signal is found. The effect of fan speed on grain quality distribution behind the clearance screen of longitudinal axial flow wheat harvester was studied. The results showed that the effect of fan speed 1100∼1200r/min on grain quality distribution was not obvious. The optimum monitoring area of the sensor was found by studying the distribution law of grain quality of the clear separation loss, and the mathematical model of the monitoring of the cleaning loss was established. The result of the model test showed that the deviation of the model was less than 1.169, and the accuracy of the model was higher. This paper presents a method for calculating the cleaning loss rate based on the feed rate of the combined harvester. The influence of the feed rate on the monitoring accuracy of the cleaning loss rate was studied by bench test. The relative error of the monitoring results is between 1.84% and 3.15%, which indicates that the combined harvester cleaning loss monitoring system developed in this paper has a high monitoring accuracy.

CONTAMINATION DEPTH OF 137CS IN CONCRETE STRUCTURES.

Uncertainty analysis for nondestructive estimation of contamination depth is presented. The contamination depth was determined using the peak-to-peak method as an in-situ measurement in which gamma spectra were measured by an HPGe detector. Since exponential activity distribution is a crucial assumption of this method, the distribution profile was confirmed by laboratory tests of core drill samples. The main parameter influencing uncertainty of contamination depth is uncertainty of relaxation length. The uncertainty is composed for statistical error represented by the ratio of net peak areas and systematic error given detection efficiency of measurement setup. Systematic relative error was evaluated to be 7.45%. Statistical relative error was evaluated to 9.97% for the proposed optimum net peak area. Variability of relaxation length was identified to be very low with mean value 2mm with standard deviation 0.73mm. For fixed relaxation length, it should be possible to estimate contamination depth by nonspectrometric devices.

Reliable and selective lead-ion sensor of sulfur-doped graphitic carbon nitride nanoflakes

An optimum large specific surface area of sulfur-doped graphitic carbon nitride nanoflakes modified glassy carbon electrode (S-g-C3N4/GCE) is reported with promising lead ion (Pb2+) detection capability. This sensor was designed and fabricated using thermal polycondesation reaction. In terms of high selectivity Pb2+ performance, we noted that the sensor exhibited appreciable detection limit of 3.0 × 10−9 mol L−1 (S/N = 3) within the ionic specimen concentration range of 7.5 × 10−8 ~ 2.5 × 10−6 mol L−1 and 2.5 × 10−6 ~ 1 × 10−3 mol L−1. Corroborated by DFT calculations, we propose that the strong interaction of S-g-C3N4 interface and Pb2+ plays an important role to generate the aforementioned sensing characteristics. In practice, we conceived high detection of Pb2+ ions that reside in lake-water and mineral samples in which percentage recovery of 88–103 can be obtained under high repetition rate. Thus, S-g-C3N4/GCE can be considered as sensitive and selective electrochemical sensor for a reliable detecting heavy metal ions in domestic sewage and industrial wastewater.

Formula Optimization of Annona muricata Folium Ethanolic Extract of Anti Acne Gel Formulation using Factorial Design Method

Acne is a pile of oil glands in the skin that are actively being clogged by dirt and infection because of Propionibacterium acnes, Staphylococcus aureus, and Staphylococcus epidermidis. The treatment for acne can use herbal ingredients, one of which is Soursop (Annona muricata L.) leaves ethanolic extract. Annona muricata folium ethanolic extract is known to have alkaloid, flavonoid and polyphenol compounds which can inhibit the growth of P. acnes, S. epidermidis, and S. aureus. Suitable dosage forms for anti-acne preparations are gels because the gel contains much water so that it provides a cooling effect on the skin due to inflammation. The purpose of this study was to determine the impact of carbopol 940 and Propylene glycol on the physical characteristics of the gel preparation and determine the optimum formula of the gel preparation using factorial design software 22 so that the gel preparation was made in four formulas. The data obtained were then analyzed using Design-Expert� and ANOVA software with a confidence level of 95%, and the determination of the optimum formula based on the optimum superimposed contour plot area. The results of the study using a factorial design approach are known that Propylene glycol has an effect on increasing the spreadability and pH while carbopol 940 has a more significant impact on the increase in adhesion and viscosity, and the optimum area of ??the composition of carbopol 940 1.536% and propylene glycol 5% was obtained.

The optimal survey area of the semi-airborne TEM method

The semi-airborne transient electromagnetic method (TEM) has been widely used in resource exploration and other fields due to its high efficiency, strong adaptability to the complex environment and high resolution. However, the conventional semi-airborne electromagnetic method continues to use the survey area of the grounded-wire TEM method. Compared with the existing ground-based TEM method, the semi-airborne TEM method is more sensitive to signal intensity because observed data is easily affected by noise for receiving position in the air. Therefore, it's unreasonable to consider only signal intensity or sensitivity related to offset in survey area. To obtain more suitable area, we discuss the distribution of the transient electromagnetic field with electrical source as well as the attenuation characteristics of the signal at different flight altitude through the forward modeling. Then, we obtain the sensitive area and flight altitude applied by the error analysis method in typical models. Finally, we describe a method what is herein dubbed the fuzzy comprehensive evaluation, which greatly reflects the membership degree of the evaluation object from different single factors to each level of fuzzy subset. Therefore, we use this method to get the optimal survey area and flight altitude under different noise levels. In low noise level, the signal intensity and sensitivity account for 33.3% and 66.7% respectively in selecting the optimum area and altitude, resulting in that the optimal area and flight altitude are coincides with the sensitive area and altitude better. While in the area filled with noise, the most area of strongest signal intensity is considered the optimal area and altitude. A field example shows that the aforementioned method can be well resolved in identifying survey lines and improving data quality.

Assessment on topographic mapping using total station and terrestrial laser scanner technology (case study: Kiara Payung area, Sumedang)

The unique capability of Terrestrial Laser Scanner (TLS) technology in observing a considerable amount of any object above the Earth’s surface opens an interesting opportunity to produce fast and reliable topographic maps. However, the use of TLS for topographic mapping should be thoroughly investigated in many aspects, including the accuracy of the observed data, the field acquisition, human resource, data processing, cost, and time acquisition. The purpose of this research is to carry out preliminary investigations. The methodology of this research consists of a reconnaissance survey, measurement planning, TLS, Total station, and Global Positioning System (GPS) data acquisition, georeferenced, filtering, 3D (Dimension) modeling and map visualization. Several aspects of the result compared with the conventional techniques by using Electronic Total Station (ETS). The results of this research show that the average error of measurements is approximately 4 mm and the detail level of the generated Digital Elevation Model (DEM) is pretty good, as it is indicated by a huge number of total point clouds (223.460 points) with the point density of about 0.25 m on optimum scanning area. TLS is suitable for a fast mapping area with a considerably large scale (1:300). In addition, based on time and human resources for mapping in the same area, the topographic mapping by TLS requires lesser time and human resources than mapping by the other methods such as ETS. The only disadvantage of using TLS is its price is still costly. As a preliminary conclusion, the TLS is more suitable to be used on high accuracy mapping, such as the reconstruction of the building, cut and fill survey, documentation of historical building.

Ultrasonic enhanced adsorption of methylene blue onto the optimized surface area of activated carbon: Adsorption isotherm, kinetics and thermodynamics

In this study, the influence of pyrolysis time and temperature on yield, fixed carbon and physicochemical properties of the biochar produced from Empty Fruit Bunch (EFB) were investigated. Response Surface Methodology was utilized to optimize the influence of process parameters on the surface area of activated carbon produced from the biochar in the absence and presence of ultrasonication and was coded EFB-AC and EFB-UAC respectively. The EFB-AC and EFB-UAC were characterized using BET, TGA, HRSEM, XRD, FTIR and XPS. The batch adsorption behavior of MB onto EFB-AC and EFB-UAC was evaluated. The results revealed that the optimum surface area (SBET) of 2114 m2/g was achieved for EFB-UAC at activation temperature (600 °C), activation time (45 min) and KOH concentration (1.5 M). It was found that EFB-UAC has high surface area, better thermal stability, better pores development and improved surface chemistry compared to the EFB-AC. The maximum adsorption of MB occurred at pH (10), adsorbent dosage (30 mg), contact time (40 min), Temperature (50 °C) and MB initial concentration (50 mg/L). The experimental data was best described by Langmuir isotherm model, having an adsorption capacity of 400 mg/g and 435 mg/g for EFB-AC and EFB-UAC, respectively. The kinetic model was best suited by pseudo-second order model for MB adsorption onto EFB-AC and EFB-UAC. The thermodynamics investigation showed that adsorption of MB was endothermic in nature due to strong electrostatic interaction and formation of hydrogen bonding. The study revealed that ultrasonic assisted variations of the adsorption parameters significantly improved the adsorption of MB onto EFB-AC and EFB-UAC.

Investigation of Al-induced electroless Sn film deposition on Cu substrate

Smooth, shiny and homogeneous tin and tin boride films have been deposited on the copper (Cu) substrates using aluminium (Al) induced electroless process. These coatings were prepared by introducing Al as a prime reducing agent. The galvanic couple between Cu-Al initiates the metal reduction reaction from a bath without traditional reducing agent and additives. Additionally sodium borohydride as a chemical reducing agent was also added for codeposition of boron. This study was conducted in the temperature range of 30 to 95 °C, though improved deposit morphology was found only above 80 °C. The optimum geometric area ratio between the substrate and Al foil surfaces was found to be 0.5. X-ray diffraction analysis confirmed the polycrystalline tetragonal structure of the deposit and crystallite size was found ~25 nm. The electrochemical measurement showed that the coupled Al can shift the Cu substrate potential negatively which enhances the rate of reduction reaction. The polarization measurements indicated the validation of mix potential theory, particularly for the tin deposition process.

Multi-criteria of wind-solar site selection problem using a GIS-AHP-based approach with an application in Igdir Province/Turkey.

Sustainable sources like wind, solar, and geothermal power are defined as a clean source of renewable energy which has a less harmful impact on the environment than other energy sources such as coal, natural gas and oil. Turkey is one of the energy-importing countries where air pollution has been become an inevitable environmental concern. Thus, investments on sustainable sources have been developed rapidly in recent years in Turkey. This paves the way for studying a site selection problem considering both solar and wind energy in Igdir Province located in the east part of Turkey. In the literature, there are many studies on solar-wind energy to select a desirable site for both energy sources, and many solution techniques have been proposed dealing with this problem. In this study, one of multi-criteria decision-making methods named analytical hierarchy process (AHP) and geographical information systems (GIS) are used to determine suitable site selection for solar-wind energy investigating four counties of Igdir: Tuzluca, Igdir Central, Karakoyunlu and Aralik. The aim of this work is first to investigate possible locations for solar-wind power plant installation using a mapping method, GIS, and then, AHP is applied to the problem to obtain optimum areas for both solar-wind energy. Also, more accurate results are provided comparing results of two methods, GIS and AHP. The results reveal that 524.5km2 for solar power plant and 147.2km2 for wind turbine are suitable while only 49.1km2 is suitable for solar-wind power plan installation.

Підвищення експлуатаційних властивостей поліграфічного обладнання

A literature analysis and patent search of technological processes for the creation of fully and partially regular micro-relief of various types and types using surface plastic deformation are carried out. Based on the inspection, the necessity of creating a combined micro-relief on flat surfaces with the task of improving the quality parameters and operational characteristics of the guides was determined. A two-stage technological process for creating micro-relief guides on flat guides of printing equipment has been developed. At the first stage of the technological process, we create a micro-relief in the form of a circle. At the second stage of the technological process, we change the modes of surface plastic deformation and, on a flat surface of the guides, a micro-rectilinear guide that passes through micro-relief circles.Experimental studies were carried out on samples of steel and cast iron. The wear resistance of samples with micro-guides was studied on a special bench. The wear of the samples by weight was estimated by the method of weight loss using laboratory analytical weights. Linear wear was indicated by measuring the depth of the micro-relief using a profilometer. The results of experimental studies have shown the optimal in terms of wear resistance area of micro-guides made of metal.The developed stage-by-stage technology makes it possible to increase the wear resistance of guides by 1.3–1.4 times in comparison with flat polished surfaces, as well as improving the geometric and physic-mechanical parameters of the surface of parts of printing equipment.An analytical relationship between the area of micro-guides and the geometric parameters of the micro-relief is established. The influence of processing modes on the geometrical parameters of the micro-relief is investigated. The optimum area from the point of view of wear resistance has been experimentally determined for the micro-guides made of metal parts.