Surface Enlargement Research Articles

Impact of urban development on streamflow regime of a Portuguese peri-urban Mediterranean catchment

Relatively little is known in the Mediterranean environment about changes in streamflow during urban development in partially urbanized peri-urban catchments. This paper explores the modification of streamflow regime as a consequence of the construction of an enterprise park, a major road, and expansion of residential areas, leading to urban areas increase from 32 to 40 % in a small catchment (6.2 km2), located in the periphery of one of the main cities in central mainland Portugal. The study was carried out over five hydrological years (October 2008–September 2009 to October 2012–September 2013), including two initial years of pre- and three following years of post-additional urban development. Streamflow was recorded by a V-notch weir at the catchment outlet at 5-min intervals. Rainfall was recorded at a weather station 0.5 km north of the catchment and by five tipping-bucket raingauges installed in January 2011 within the study catchment. Streamflow was converted into runoff and split into baseflow and stormflow components by applying a mathematical low-pass digital filter. Streamflow differences were investigated through changes in (i) annual runoff coefficients, (ii) annual baseflow index, (iii) seasonal baseflow index and stormflow coefficient, and (iv) storm event analysis. Annual runoff coefficient ranged from 14 to 21 % and storm runoff coefficient from 9 to 14 %, both between the driest 2011/12 and wettest 2012/13. Although these differences were influenced by inter-annual weather variability, a comparison between years with similar rainfall before and after additional urban development showed a 43 % increase in storm runoff. Impacts on streamflow were also noticed through changes on hydrograph: (i) regression lines of storm runoff against rainstorm parameters exhibited higher vertical positions in 2012/13 than 2008/09, (ii) gradual increase in peak flow but with a clear distance between pre- and post- additional urbanization, (iii) quicker response time from 60–75 min to 40–45 min between both periods, and (iv) decrease in recession time from 21–29 h to 7–9 h for the same periods. The dispersed urban pattern and permeable soils provide many overland flow sinks, favouring relatively low storm runoff of the catchment. Nevertheless, the enlargement of impervious surfaces (from 12.8 to 17.0 %) and particularly the storm drainage system installed in new urban areas led to great changes on rainfall–runoff event responses. Urban planning should consider the landscape mosaic of peri-urban areas in order to maximize water infiltration and minimize the impacts on streamflow regime.

Rumen papillae morphology of beef steers relative to gain and feed intake and the association of volatile fatty acids with kallikrein gene expression

Feed costs are the most expensive input in beef production. Improvement in the ability of beef cattle to convert feed into meat would lower feed inputs and reduce the cost of production. The rumen epithelium is responsible for absorption and metabolism of nutrients and microbial by-products, and may play a significant role in gain or feed intake. Our objective was to determine the relationships among rumen papillae morphology, gene expression, volatile fatty acid concentrations, and gain and feed intake. Average daily gain (ADG) and average daily feed intake (ADFI) were collected on a crossbred population of beef steers over three feeding trials. Based on feed intake and weight gain differences, 48 steers were selected for the project (16 from each feeding study). At harvest, rumen epithelial samples were taken from three locations in the rumen of each animal. The number of papillae on 1cm2 of epithelium was counted to determine density. Papillae (n=30) from each sample were measured for length and width. The density, length, and width were combined to determine surface enlargement factor (SEF). None of the morphological characteristics of the papillae (length, width, density or SEF) were associated with feed intake or gain (P≥0.10). Ruminal fluid was collected from steers (n=15) in the third trial for volatile fatty acid (VFA) analysis to determine if a relationship between VFA and ADG or ADFI existed. No differences in volatile fatty acid (VFA) concentrations were associated (P≥0.17) with ADFI or ADG. VFA variation was also evaluated for a relationship with kallikrein (KLK) genes since ruminal butyrate concentrations have previously been associated with the transcript abundance KLK genes. Additionally, qRT-PCR data showed that variation in the transcript abundance of KLK6,8-10, and 13 associated with feed intake in our first trial of steers. Thus, we evaluated the transcript abundance of eight KLK genes in rumen papillae from steers in the third trial (n=16). Expression levels of KLK5 correlated with valerate concentrations in the rumen (P<0.05), KLK10 correlated with acetate concentrations in the rumen (P<0.05), KLK12 correlated with acetate and butyrate concentrations in the rumen (P<0.05), and the expression levels of KLK9 and KLK10 were associated with gain. While rumen papillae morphology was not associated with beef steer gain or intake, our data suggests members of the kallikrein gene family have a relationship with the VFA environment in the rumen, and also appear to play a role in the highly correlated traits of ADG and ADFI.

Diamond-Based Supercapacitors: Realization and Properties.

In this Spotlight on Applications, we describe our recent progress on the fabrication of surface-enlarged boron-doped polycrystalline diamond electrodes, and evaluate their performance in supercapacitor applications. We begin with a discussion of the fabrication methods of porous diamond materials. The diamond surface enlargement starts with a top-down plasma etching method. Although the extra surface area provided by surface roughening or nanostructuring provides good outcome for sensing applications, a capacitance value <1 mF cm-2 or a surface-enlargement factor <100 fail to meet the requirement of a practical supercapacitor. Driven by the need for large surface areas, we recently focused on the tempated-growth method. We worked on both supported and free-standing porous diamond materials to enhance the areal capacitance to the "mF cm-2" range. With our newly developed free-standing diamond paper, areal capacitance can be multiplied by stacking multilayers of the electrode material. Finally, considering the fact that there is no real diamond-based supercapacitor device up to now, we fabricated the first prototype pouch-cell device based on the free-standing diamond paper to evaluate its performance. The results reveal that the diamond paper is suitable for operation in high potential windows (up to 2.5 V) in aqueous electrolyte with a capacitance of 0.688 mF cm-2 per layer of paper (or 0.645 F g-1). Impedance spectroscopy revealed that the operation frequency of the device exceeds 30 Hz. Because of the large potential window and the ability to work at high frequency, the specific power of the device reached 1 × 105 W kg-1. In the end, we made estimations on the future target performance of diamond supercapacitors based on the existing information.

Impact of contact pressure on output voltage of triboelectric nanogenerator based on deformation of interfacial structures

A micro- and nano-structure at the contact interface of triboelectric nanogenerator (TENG) is an essential element enabling a remarkable performance improvement. Despite the various innovative inventions of interfacial structures, there has been little understanding about the analytical interpretation of the contact interface. Herein, the deformation behavior of interfacial micro- and nano-structures during the contact process is systematically analyzed to clarify the origin of the contact pressure to output voltage relationship of TENG. The visualization experiment, simulation, theoretical modeling, and electrical measurements are conducted for the comprehensive analysis. The results confirm that the deformation of interfacial structures directly determines the pressure–voltage relationship of TENG. The surface enlargement effect by interfacial nanostructure formation becomes completely valid only when the provided contact pressure is stronger than the certain threshold pressure to make the full-contact condition. Due to the correlation between contact pressure and output voltage, interfacial structure of the TENG should be carefully customized depending on the application environment. Based on the analyzed pressure–voltage relationship of the TENG, a hybrid circuit for energy scavenging and digital pressure sensing is designed and experimentally demonstrated.

Dissimilar joining of aluminum alloy and stainless steel thin sheets by thermally assisted plastic deformation

Aluminum alloy/steel hybrid components are widely used in different industrial areas because of their high performance. However, the high importance of reducing the thickness of components to realize lightweight products requires the dissimilar joining of Al alloy and steel thin sheets (less than 1mm in thickness), which is a major challenge using current joining technologies. In this paper, an alternative dissimilar joining process by thermally assisted plastic deformation is proposed for thin metallic sheets. The effects of various parameters on the joining performance were investigated. After exposure to an elevated temperature of 450°C for 22s, an optimized joint type was achieved by local plastic deformation using a punch-die pair. This joint type exhibited an average joint efficiency factor of 85.2%, and an average absorption energy of 1.69kNmm in tensile shear tests, as well as satisfactory joining performance in peel tests. In addition to mechanical anchoring and surface enlargement, atomic interdiffusion at the interface activated by the elevated forming temperature was found to be critical for obtaining high joining quality. The thickness of the Fe-Al interdiffusion layer at the interface was positively correlated with the heat input and the locally distributed plastic strain. This study shows that the proposed dissimilar joining process for Al alloy and steel thin sheets is a promising joining method for Al alloy/steel lightweight structures owing to the excellent joining performance, weight effectiveness, simple operation and long tool lifetime.

A compression-torsion-wear-test achieving contact pressures of up to eight times the initial flow stress of soft aluminium

Different experiments exist for the characterization of friction and wear in metal forming, which try to reproduce the tribological conditions of the forming process as precisely as possible. A particular challenge arises from processes such as cold extrusion, with contact stresses that are several times higher than the initial flow stress of the workpiece material. In this paper, a new experimental setup for wear testing is presented and compared with available tests concerning contact pressure, surface enlargement and sliding velocity. Using a special encapsulation of the specimen, the newly developed compression-torsion-wear-test is able to scale the contact pressure to a multiple of the initial flow stress of soft aluminium.

Low Density Growth of Graphene by Air Introduction in Atmospheric Pressure Chemical Vapor Deposition

Chemical vapor deposition (CVD) is a promising method to produce large-size single-crystal graphene, and further increase in domain size is desirable for electro/optic applications. Here we studied the effect of low amount of air introduction by intentional leak on graphene growth in atmospheric pressure CVD. The air introduction at the heating process resulted in roughening of Cu surface induced by oxygen, while air introduction at the annealing under H2 ambient drastically decreased graphene density due to reduction of active sites for graphene nucleation both by surface oxidation and enlargement of Cu domain. Although air introduction only at the growth stage was ineffective for graphene nucleation, air introduction for both annealing and growth provided great enhancement of domain growth without increasing the density of graphene, which is an optimized condition to obtain a large single-crystal. This controlled introduction of air in atmospheric pressure CVD provided ∼ 2.5 mm hexagonal single layer graphene with high quality. [DOI: 10.1380/ejssnt.2015.404]

Laser induced nano‐porous Ti–O‐layers for durable titanium adhesive bonding

For the integration of titanium in lightweight construction, adhesive bonding technology offers several advantages. Required wet‐chemical surface pre‐treatments of titanium are associated with high process effort, often harmful waste and in most cases insufficient durability of the adhesive bonds. In the present work, titanium is pre‐treated by an Nd : YAG laser (λ = 1064 nm), whereby a stable nanostructured oxide layer is generated. This layer provides a significant surface enlargement for durable adhesive bonding. The growth mechanism of such nano‐structures was examined by means of analytical methods.

Diamond-coated silicon wires for supercapacitor applications in ionic liquids

For a long time sp2 carbon has been the dominating material for supercapacitor applications. In this paper a new concept of using boron-doped diamond for supercapacitors is proposed. Diamond surface enlargement is realized via bottom-up template-growth. In this method, silicon nanowire electrodes are coated with a thin (~100nm) layer of nanocrystalline diamond (NCD) by microwave enhanced chemical vapor deposition (MWCVD). The quality of overgrowth is characterized by high resolution scanning electron microscopy which reveals a homogeneous coverage of diamond on Si nanowire surface. To enhance the potential window to 4V, a room temperature ionic liquid is used as electrolyte. The dilution of the ionic liquid is investigated in terms of conductivity and specific capacitance. The capacitance as measured via cyclic voltammetry reaches 105μF/cm2. An energy density of 84μJ/cm2 and a high power density of 0.94mW/cm2 are obtained in combination with good stability of over 10,000charging/dischargingcycles.

Effect of Surface Enlargement and of Viscosity of Lubricants on Friction Behaviour of Advanced High Strength Steel Material during Deep Drawing

Increasing demands on vehicle safety and weight reduction in the automotive industry lead to an increased use of “advanced high strength steels” for car body manufacturing purposes. Mentioned material grades are having high levels of tensile strength and are often used in conventional sheet metal forming processes. One of the most significant factors on quality of stamped components as well as its manufacturing process robustness is the friction between tool and sheet material. During the deep drawing process, superposition of tensile stresses is causing enlargement of the sheet surface by a few percent. This effect can damage the zinc layer. Due to that fact, lubricant has to keep tool and work piece separated in order to prevent adhesion and abrasion. For that very reason, sufficient amount of lubricant has to be applied onto the surface texture reservoirs. Furthermore, the viscosity of lubricant is mainly influencing its ability of wetting the surface. The aim of this study is to define the relationship between friction coefficient, surface enlargement and lubrication having different viscosities. In this investigation the same amount of lubricant with viscosity of ϑ=65 mm2/s, ϑ=200 mm2/s and ϑ=400 mm2/s was applied on strips made out of DP1000 and DC04 steel. Then, the strips were stretched uniaxially, and restraining forces were measured by strip draw test considering constant surface pressure and drawing speed. In this paper, the correlation between friction coefficient, viscosity and surface enlargement for two different sheet material grades is shown.

Myosin VIIA is a marker for the cone accessory outer segment in zebrafish.

The accessory outer segment, a cytoplasmic structure running alongside the photoreceptor outer segment, has been described in teleost fishes, excluding the model organism zebrafish. So far, the function of the accessory outer segment is unknown. Here, we describe the ultrastructure of the zebrafish cone accessory outer segment by electron microscopy. Starting at the connecting cilium, the accessory outer segment runs parallel alongside the cone outer segment (COS). A thin plasma bridge connects the outer segment with the accessory outer segment, whose surface is enlarged by foldings and invaginations. Beside the morphological descriptions, we demonstrate that the Usher protein myosin VIIa (Myo7a) is a specific marker for the zebrafish cone accessory outer segment. Zebrafish cone photoreceptors possess a large and well-differentiated accessory outer segment, in which the unconventional motor protein Myo7a is highly enriched. The direct cytoplasmic contact with the COS as well as the surface enlargement of the accessory outer segment suggests an important role of this structure in transport and exchange of metabolites between the COS and the surrounding retinal pigment epithelium. In future studies of the outer retina, more attention should be paid to this often neglected structure.

A New Concept of the Sliding Compression Test to Independently Investigate the Contact Normal Stress and the Surface Enlargement

Cold forging is a highly efficient process to produce components. However, the occurring tribological loads are tremendous. Therefore, complex tribological systems are necessary. They can be influenced by numerous factors. Most important are the tribological loads, which can usually be investigated independently. On the other hand, the contact normal stress and the surface enlargement are coupled in tribometer tests. In order to investigate them independently, a new concept for the Sliding Compression Test is presented and verified. This procedure reveals that both values have an influence on the friction coefficient. However, the influence of the surface enlargement is with about two-thirds higher.

The comparative gastrointestinal morphology of five species of muroid rodents found in Saudi Arabia

Meriones rex (King jird), Meriones libycus (Libyan jird), Acomys dimidiatus (Eastern spiny mouse), Acomys cahirinus (Egyptian spiny mouse), and Dipodillus dasyurus (Wagner's dipodil) are five species of small rodents of the superfamily Muroidea with distributions in Eastern Africa, Egypt, and the desert regions of the Arabian Peninsula. Water is scarce in these regions and may result in relatively low-digestible food. The aim of the present study is to describe and compare the gastrointestinal tract morphology and morphometry of these five species in order to elucidate whether morphology is influenced by phylogeny or dietary preference. Each segment of the gastrointestinal tract of each species was macroscopically examined and the length and basal surface area of each segment was measured. Standard histologic procedures were performed to determine a surface enlargement factor to determine the mucosal luminal surface area. A unilocular-hemiglandular stomach was observed in all the species examined. The caeca of all the species were long and arranged into a loose spiral toward the caecal tip with the ileocaecal and caeco-colic openings positioned close together. Two rows of oblique folds could be observed in the proximal colon of all species except in D. dasyurus which had longitudinal folds. Morphometric analysis showed the largest stomach in A. cahirinus and the largest caecum and colon in M. libycus. All the species can be grouped in the family Muridae in two subfamilies and similarities were observed including the hemiglandular stomach and relatively large caecum. It could be concluded that phylogeny plays an important role in determining gastrointestinal morphology while diet plays a subordinate role in the desert rodents in the present study.

Drug loading into porous calcium carbonate microparticles by solvent evaporation

Drug loading into porous carriers may improve drug release of poorly water-soluble drugs. However, the widely used impregnation method based on adsorption lacks reproducibility and efficiency for certain compounds. The aim of this study was to evaluate a drug-loading method based on solvent evaporation and crystallization, and to investigate the underlying drug-loading mechanisms. Functionalized calcium carbonate (FCC) microparticles and four drugs with different solubility and permeability properties were selected as model substances to investigate drug loading. Ibuprofen, nifedipine, losartan potassium, and metronidazole benzoate were dissolved in acetone or methanol. After dispersion of FCC, the solvent was removed under reduced pressure. For each model drug, a series of drug loads were produced ranging from 25% to 50% (w/w) in steps of 5% (w/w). Loading efficiency was qualitatively analyzed by scanning electron microscopy (SEM) using the presence of agglomerates and drug crystals as indicators of poor loading efficiency. The particles were further characterized by mercury porosimetry, specific surface area measurements, differential scanning calorimetry, and USP2 dissolution. Drug concentration was determined by HPLC. FCC–drug mixtures containing equivalent drug fractions but without specific loading strategy served as reference samples. SEM analysis revealed high efficiency of pore filling up to a drug load of 40% (w/w). Above this, agglomerates and separate crystals were significantly increased, indicating that the maximum capacity of drug loading was reached. Intraparticle porosity and specific surface area were decreased after drug loading because of pore filling and crystallization on the pore surface. HPLC quantification of drugs taken up by FCC showed only minor drug loss. Dissolution rate of FCC loaded with metronidazole benzoate and nifedipine was faster than the corresponding FCC–drug mixtures, mainly due to surface enlargement, because only small fractions of amorphous drug (12.5%, w/w, and 8.9%, w/w, respectively) were found by thermal analysis. Combination of qualitative SEM analysis and HPLC quantification was sufficient to proof the feasibility of the solvent-evaporation method for the loading of various drugs into FCC. Mechanistic investigation revealed that a high specific surface area of the carrier is required to facilitate heterogeneous nucleation, and large pore sizes (up to 1μm) are beneficial to reduce crystallization pressures and allow drug deposition within the pores. The solvent-evaporation method allows precise drug loading and appears to be suitable for scale-up.

Effect of the primary heat treatment on the bond formation in cold welding of aluminum and steel by cold forging

Cold forging enables the manufacturing of high strength monolithic components. When used as joining technology it can also be extended to an enabler of multi-material product design. The contact conditions at the interface between the components during the cold forging process play a crucial role. The joining of two billets of steel and aluminum is investigated by a finite element analysis with regard to the material distribution and the effect of a primary heat treatment of both materials. These parameters affect the surface enlargement and the contact normal stress which are decisive parameters for the formation of a sound bond between aluminum and the hardly cold weldable steel. The experimental results present the effect of a primary heat treatment on the bond formation. Microscopic analyses of the bond formation allow a deeper insight into the bonding mechanism. Thus, the results lead to process design guidelines for cold welding by cold forging.

Experimental Investigations of Thermal Joining of Polyamide Aluminum Hybrids Using a Combination of Mono- and Polychromatic Radiation

In recent years, the joining of plastics and metals for lightweight constructions has become more and more important for industrial applications. This paper presents experimental investigations of transmission joining of polyamide aluminum hybrids using a combination of mono- and polychromatic radiation. The used experimental setup consists of a diode laser, a laser processing head with additional infrared emitters, a robot and a clamping device for lap joints. With this setup, experiments are performed to determine a process window for the thermal joining of polyamide aluminum hybrids and to evaluate geometrical, material-related and process-related limits of the approach. For that, hybrid joints of aluminum with sheet thicknesses of 0.6 mm to 1.0 mm and 3mm thick unfilled polyamide 6 are used. To improve the mechanical interlocking between the polyamide and the aluminum surface a prior laser structuring of the metal is done by a ns-Nd:YAG-laser. Primarily,the influence of surface roughness and surface enlargement on the optical properties of aluminum and the mechanical properties of the joined specimens is investigated.

Surface enlargement of a new arterialised venous flap by the surgical delay method.

The delay method is a surgical, pharmacological and combined method that includes two or more time separated phases, which gives bigger flap surface. In our research we explored the possibility of flap surface enlargement in a new arterialised venous flap (AVF) on an experimental rabbit ear model by the delay surgical method. The aim of this research was to establish vitality surface of our AVF and to maintain the difference in flap vital surface between AVF flaps, with or without performing the delay surgery method. We used both ears of "Big Chinchilla" rabbits in 10 experimental male animals, divided into two groups, average weight 3-3.5 kg, and average age 8-10 months. In the first (experimental) group, a venous flap was arterialised by our method. In the second (control) group, the venous flap was arterialised 14 days after the delay surgical method. AVF surface was measured on the 1 and 14 days by the method of trapezoid rule. Vital surface on our AVF experimental model was bigger than 87% of elevated flap surface after the delay surgical method. Vital surface on AVF without delay on our experimental model was bigger than 30% of elevated flap surface (p < 0.001). Analysis of previous experimental models on the rabbit ear, non-delayed and delayed (to enlarge flap surface) led us to conclusion that previously created experimental models of non-delayed AVF are hemodynamically negative. Our experimental non-delay AVF model is hemodynamically more positive than previously created models of non-delay AVF and provides better conditions for AVF survival and enlargement of vital flap surface of elevated flap. On the other hand, surgical delay method significantly enlarges vital surface of AFF.

Computer Aided Stereometric Evaluation of Porostructuralosteoconductive Properties of Intra-Osseous Implant Porous Coatings

Abstract The proper interaction of bone tissue - the natural porous biomaterial - with a porous coated intra-osseous implant is conditioned, among others, by the implant porous coating poroaccessibility for bone tissue adaptive ingrowth. The poroaccessibility is the ability of implant porous coating outer layer to accommodate the ingrowing bone tissue filling in its pore space and effective new formed bone mineralizing in the pores to form a biomechanically functional bone-implant fixation. The functional features of the microtopography of intra-osseous implant porous surfaces together with the porosity of pore space of the outer layer of the porous coating are called by bioengineers the porostructural-osteoconductive properties of the porous coated implant. The properties are crucial for successful adaptive bone tissue ingrowth and further long-term (secondary) biomechanical stability of the boneimplant interface. The poroaccessibility of intra-osseous implants porous coating outer layers is characterized by - the introduced in our previous papers - set of stereometric parameters of poroaccessibility: the effective volumetric porosity fVef, the index of the porous coating space capacity VPM, the representative surface porosity fSrep, the representative pore size pSrep, the representative angle of the poroaccessibility Wrep and the bone-implant interface adhesive surface enlargement index y. Presented in this paper, an original method of evaluation of the porostructural-osteoconductive properties of intra-osseous implant porous coatings outer layer by means of the parameters of poroaccessibility was preliminary verified during experimental tests performed on the representative examples of porous coated femoral stems and acetabular cups of various hip endoprostheses. The computer-aided stereometric evaluation of the microstructure of implant porous coatings outer layer can be now realized by the authoring application software PoroAccess_1.0 elaborated in our research team in Java programming language

Electrochemical Dissolution and Passivation of Cu-Ni Alloys in Sodium Sulphate Aqueous Solution

The electrochemical behaviour of two copper-nickel alloys is studied in 0.1 M Na2SO4 using cyclic voltammetry, potentiodynamic and current time transient techniques. The microstructure of the compounds formed during anodic sweep is characterized using x-ray diffraction analysis. The forward sweep is characterized by the existence of two well-defined potential regions; the selective dissolution and the simultaneous dissolution potential regions. The first potential region consisted in two anodic peaks A1 and A2 corresponding to the formation of Ni(OH)2 and NiO, and Cu2O, respectively. The second potential region consisted in two anodic peaks A3 and A4 corresponding to the formation of CuO and Ni2O3, respectively. It is found that the Cu-Ni system in sulphate solution follows the dissolution-redeposition mechanism of the dissolution of metals from the alloys. The X-ray diffraction analysis confirmed the existence Ni2O3 and CuO on the electrode surface of nickel rich alloy polarized to potential more noble than the potential of A4 and the existence of Cu2O and NiO on the surface of copper-rich alloy polarized to a potential in the A2 region. Atomic Force microscope images show surface enlargement beyond the critical potential Ecrit.

Diamond foam electrodes for electrochemical applications

Nano-structured electrodes become promising materials for a vast number of applications such as bio-chemical sensing and supercapacitors. We introduce a new concept to generate surface enlarged diamond electrodes, so-called “diamond foam”. To obtain diamond foam electrodes, SiO2 spheres were used for heavily boron-doped (1021cm−3) nano-crystalline diamond (B-NCD) overgrowth in a microwave plasma reactor. After overgrowth with B-NCD the SiO2 spheres were etched away with HF giving rise to diamond foam consisted of B-NCD shells accumulated on the substrate. This process has the advantage that the thickness of diamond foam can increase infinitely by repeating the growth and etching processes. Structural and electrochemical characterizations show that the diamond foam electrodes show a surface enlargement of around 40 while keeping good chemical stability as well as a diamond related structural properties.