Larval morphology and new records of the iconic diving beetle Acilius sinensis Peschet, 1915 (Coleoptera: Dytiscidae: Dytiscinae)-a species well established in western Yunnan, China.

Adults and larvae of the very rare Chinese endemic species Acilius sinensis Peschet, 1915 are newly reported from three localities in western Yunnan, which indicates the presence of viable populations in this area. Based on the available data, the rarity of the species in collections is more caused by collecting bias than actual threat of its habitat loss. All larval instars of A. sinensis are for the first time described according to the now generalized larval descriptive format of Dytiscidae, which incorporates detailed chaetotaxic and morphometric analyses. Like other known Acilius Leach, 1817 larvae, A. sinensis is characterized by the typical Y-shaped median process of prementum. So far as the third instar larva is considered, A. sinensis shares with A. fraternus (Harris, 1828), A. kishii Nakane 1963, A. semisulcatus Aubé, 1838, and A. sulcatus (Linnaeus, 1758) the median process of prementum invaginated at nearly 75% of its length compared to less than 35% in A. abbreviatus Aubé, 1838, A. duvergeri Gobert, 1874, and A. canaliculatus (Nicolai, 1822). As far as chaetotaxy is concerned, A. sinensis is distinguished by the presence of the primary pore PAo located on the ventral face of the parietal. The habitat of the species is briefly commented. Acilius sinensis is here newly proposed for inclusion in the IUCN red list in the category Vulnerable.

Austrelatus gen. nov., a new genus of Australasian diving beetles (Coleoptera, Dytiscidae, Copelatinae), with the discovery of 31 new species from New Guinea.

Herein, Austrelatusgen. nov. (type species: Copelatusirregularis W.J. Macleay, 1871) is described for a distinctive lineage of predominantly Australasian species previously assigned to Copelatus Erichson, 1832. The new genus was retrieved as well supported, monophyletic clade in phylogenetic analysis of DNA sequences data using Bayesian and parsimony approaches. The main morphological diagnostic character of Austrelatus is a complex median lobe of the aedeagus, with evident dorsal and ventral sclerites usually divided in apical half into two lobes of different shape or otherwise modified. Morphological comparison of the new genus with other Copelatinae genera, especially with Copelatus and Exocelina Broun, 1886, and a generic key to the New Guinean Copelatinae are provided. New combinations are established for 31 already described species mainly from the Australian Region (all from Copelatus): Austrelatusadelbert (Megna, Atthakor, Manaono, Hendrich & Balke, 2017), comb. nov.; A.badeni (Sharp, 1882), comb. nov.; A.bakewelli (J. Balfour-Browne, 1939), comb. nov.; A.baranensis (Hájek, Shaverdo, Hendrich & Balke, 2021), comb. nov.; A.bougainvillensis (Hájek, Shaverdo, Hendrich & Balke, 2021), comb. nov.; A.boukali (Hendrich & Balke, 1998), comb. nov.; A.clarki (Sharp, 1882), comb. nov.; A.daemeli (Sharp, 1882), comb. nov.; A.davidi (Wewalka, 2017), comb. nov.; A.deccanensis (Sheth, Ghate & Hájek, 2018), comb. nov.; A.fidschiensis (Zimmermann, 1928), comb. nov.; A.gestroi (Régimbart, 1892), comb. nov.; A.irregularis (W.J. Macleay, 1871), comb. nov.; A.kaszabi (Guignot, 1956), comb. nov.; A.kietensis (Hájek, Shaverdo, Hendrich & Balke, 2021), comb. nov.; A.laevipennis (Hájek, Shaverdo, Hendrich & Balke, 2021), comb. nov.; A.luteomaculatus (Guignot, 1956), comb. nov.; A.maushomi (Sheth, Ghate & Hájek, 2018), comb. nov.; A.neoguineensis (Zimmermann, 1919), comb. nov.; A.nigrolineatus (Sharp, 1882), comb. nov.; A.papuensis (J. Balfour-Browne, 1939), comb. nov.; A.parallelus (Zimmermann, 1920a), comb. nov.; A.schuhi (Hendrich & Balke, 1998), comb. nov.; A.sibelaemontis (Hájek, Hendrich, Hawlitschek & Balke, 2010), comb. nov.; A.strigosulus (Fairmaire, 1878), comb. nov.; A.ternatensis (Régimbart, 1899), comb. nov.; A.uludanuensis (Hendrich & Balke, 1995), comb. nov.; A.urceolus (Hájek, Shaverdo, Hendrich & Balke, 2021), comb. nov.; A.variistriatus (Hájek, Shaverdo, Hendrich & Balke, 2021), comb. nov.; A.wallacei (J. Balfour-Browne, 1939), comb. nov. and A.xanthocephalus (Régimbart, 1899), comb. nov.Austrelatus species from New Guinea are divided into two informal species groups, the A.neoguineensis group and A.papuensis group, and A.fumatosp. nov. and A.setiphallussp. nov. standing aside of them. The A.neoguineensis group is introduced with three previously known species and 29 new species described here based on the morphological characters and Cox1 data: Austrelatusbaliemsp. nov., A.bormensissp. nov., A.brazzasp. nov., A.debulensissp. nov., A.fakfaksp. nov., A.febrisaurisp. nov., A.fojaensissp. nov., A.garainensissp. nov., A.innominatussp. nov., A.lembenensissp. nov., A.lisaesp. nov., A.manokwariensissp. nov., A.mimikasp. nov., A.mirificussp. nov., A.moreguinensissp. nov., A.nadjaesp. nov., A.oksibilensissp. nov., A.pseudoneoguineensissp. nov., A.pseudoksibilensissp. nov., A.rajaampatensissp. nov., A.rouaffersp. nov., A.rugosussp. nov., A.sandaunensissp. nov., A.sarmiensissp. nov., A.securiformissp. nov., A.testegensissp. nov., A.toricellisp. nov., A.vagauensissp. nov., and A.wanggarensissp. nov.Copelatusvagestriatus Zimmermann, 1919, syn. nov. is recognised as a junior subjective synonym of A.clarki (Sharp, 1882). The lectotypes of Copelatusgestroi Régimbart, 1892, C.neoguineensis Zimmermann, 1919 and C.xanthocephalus Régimbart, 1899 are designated. All species are (re)described, and their important species characters (genitalia, habitus, and colour patterns) are illustrated. Keys to all species are provided. The known distribution and habitat preferences of each species are outlined briefly. New Guinean Austrelatus occupy a variety of stagnant water habitats, either lentic sensu stricto, or standing water associated with lotic habitats (e.g., backflows, rockpools, intermittent / ephemeral stream pools).

Mechanical Properties of High Carbon Low-Density Steels.

The paper presents the possibilities of heat treatment of low-density structural steels usable for springs. Heats have been prepared with chemical compositions 0.7 wt% C and 1 wt% C, as well as 7 wt% Al and 5 wt% Al. Samples were prepared from ingots weighing approximately 50 kg. These ingots were homogenised, then forged, and hot rolled. Primary transformation temperatures and specific gravity values were determined for these alloys. For low-density steels, there usually needs to be a solution to achieve the required ductility values. At cooling rates of 50 °C/s and 100 °C/s, the kappa phase is not present. A SEM analysed the fracture surfaces for the presence of transit carbides during tempering. The martensite start temperatures ranged from 55-131 °C, depending on the chemical composition. The densities of the measured alloys were 7.08 g/cm3 and 7.18 g/cm3, respectively. Therefore, heat treatment variation was carried out to achieve a tensile strength of over 2500 MPa, with ductility of almost 4%. Hardnesses above 60 HRC were achieved for 1 wt% C heats using the appropriate heat treatment.

Morphology of the larvae of Sandracottus femoralis Heller, 1934, and S. mixtus (Blanchard, 1843) and phylogenetic comparison with other known Aciliini (Coleoptera: Dytiscidae, Dytiscinae).

We describe the larvae of the diving-beetle genus Sandracottus Sharp, 1882 based on S. femoralis Heller, 1934 and S. mixtus (Blanchard, 1843). We include detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, terminal abdominal segment and urogomphi in order to discover useful characters for distinguishing Sandracottus larvae from those of other known Aciliini (Coleoptera: Dytiscidae, Dytiscinae). A provisional parsimony analysis based on larval characteristics of seven Aciliini species in four genera (Acilius Leach, 1817, Graphoderus Dejean, 1833, Sandracottus, Thermonectus Dejean, 1833) was conducted using the program TNT. A clade grouping Eretini and Aciliini stands out as the most strongly supported in this analysis. The tribe Aciliini finds itself monophyletic with also very good support. Our analysis, however, failed to depict any clear phylogenetic relationships within the Aciliini although each of the four genera studied emerged from our study as morphologically distinct.

A New Alloying Concept for Low-Density Steels.

This paper introduces a new alloying concept for low-density steels. Based on model calculations, samples-or "heats"-with 0.7 wt% C, 1.45 wt% Si, 2 wt% Cr, 0.5 wt% Ni, and an aluminium content varying from 5 to 7 wt% are prepared. The alloys are designed to obtain steel with reduced density and increased corrosion resistance suitable for products subjected to high dynamic stress during operation. Their density is in the range from 7.2 g cm-3 to 6.96 g cm-3. Basic thermophysical measurements are carried out on all the heats to determine the critical points of each phase transformation in the solid state, supported by metallographic analysis on SEM and LM or the EDS analysis of each phase. It is observed that even at very high austenitisation temperatures of 1100 °C, it is not possible to change the two-phase structure of ferrite and austenite. A substantial part of the austenite is transformed into martensite during cooling at 50 °C s-1. The carbide kappa phase is segregated at lower cooling rates (around 2.5 °C s-1).

Lignocellulosic Bioethanol and Biobutanol as a Biocomponent for Diesel Fuel.

In this paper, the fuel properties of mixtures of diesel fuel and ethanol and diesel fuel and butanol in the ratio of 2.5% to 30% were investigated. The physicochemical properties of the blends such as the cetane number, cetane index, density, flash point, kinematic viscosity, lubricity, CFPP, and distillation characteristics were measured, and the effect on fuel properties was evaluated. These properties were compared with the current EN 590+A1 standard to evaluate the suitability of the blends for use in unmodified engines. The alcohols were found to be a suitable bio-component diesel fuel additive. For most physicochemical properties, butanol was found to have more suitable properties than ethanol when used in diesel engines. The results show that for some properties, a butanol-diesel fuel mixture can be mixed up to a ratio of 15%. Other properties would meet the standard by a suitable choice of base diesel.

Use of Dicyclopentadiene and Methyl Dicyclopentadiene for the Synthesis of Unsaturated Polyester Resins.

Dicyclopentadiene (DCPD) modified unsaturated polyester resins (UPRs) are mostly used for hulls, decks, and bathroom facilities. Main advantages of these polymers over orthophthalic or isophthalic polyesters are their relatively low shrinking, reduced styrene emission, lower cost, and fast curing in thin layers. On the other hand, once cured, these materials are more brittle and have lower glass transition temperatures and lower chemical resistance due to their different chemical constitutions. DCPD UPRs with standard grades are usually produced with high-quality DCPD (over a 85% purity) using the so-called "water process", a synthesis consisting of two reaction steps. An adduct of maleic anhydride with DCPD is firstly formed with water, and then, it reacts with the other esterification monomers such as acids and glycols. DCPD raw materials used in this study were prepared by a unique distillation process developed by ORLEN Unipetrol and University of Chemistry and Technology, Prague. This technology allows producing a wide spectrum of DCPD quality by adjusting the content of another norbornene dimer: methyl dicyclopentadiene (MeDCPD). The influence of MeDCPD on unsaturated polyester properties was examined throughout this study. It has been discovered that in low concentrations, MeDCPD had a slight influence on flexural mechanical properties whereas its concentrations up to 65% led to a softer and brittle material. Nevertheless, by adjusting the unsaturation degree, it has been shown that MeDCPD may be successfully implanted in UPR formulation.

Advanced Biofuels Based on Fischer-Tropsch Synthesis for Applications in Diesel Engines.

This paper focuses on the evaluation of the fuel properties of Fischer-Tropsch diesel blends with conventional diesel. Incorporating this advanced fuel into conventional diesel production will enable the use of waste materials and non-food materials as resources, while contributing to a reduction in dependence on crude oil. To evaluate the suitability of using Fischer-Tropsch diesel, cetane number, cetane index, CFPP, density, flash point, heat of combustion, lubricity, viscosity, distillation curve, and fuel composition ratios using multidimensional GC × GC-TOFMS for different blends were measured. It was found that the fuel properties of the blended fuel are comparable to conventional diesel and even outperform conventional fuel in some parameters. All measurements were performed according to current standards, thus ensuring the repeatability of measurements for other research groups or the private sector.

Advanced Biofuels Based on Fischer-Tropsch Synthesis for Applications in Gasoline Engines.

The aim of the article is to determine the properties of fuel mixtures of Fischer-Tropsch naphtha fraction with traditional gasoline (petrol) to be able to integrate the production of advanced alternative fuel based on Fischer-Tropsch synthesis into existing fuel markets. The density, octane number, vapor pressure, cloud point, water content, sulphur content, refractive index, ASTM color, heat of combustion, and fuel composition were measured using the gas chromatography method PIONA. It was found that fuel properties of Fischer-Tropsch naphtha fraction is not much comparable to conventional gasoline (petrol) due to the high n-alkane content. This research work recommends the creation of a low-percentage mixture of 3 vol.% of FT naphtha fraction with traditional gasoline to minimize negative effects-similar to the current legislative limit of 5 vol.% of bioethanol in E5 gasoline. FT naphtha fraction as a biocomponent does not contain sulphur or polyaromatic hydrocarbons nor benzene. Waste materials can be processed by FT synthesis. Fischer-Tropsch synthesis can be considered a universal fuel-the naphtha fraction cut can be declared as a biocomponent for gasoline fuel without any further necessary catalytic upgrading.

A review of Copelatus diving beetles from the Solomon Islands, reporting the discovery of six new species (Coleoptera, Dytiscidae, Copelatinae).

The first account of the genus Copelatus Erichson, 1832 in the Solomon Islands is provided, reporting 10 species for the Archipelago. Six of these are new to science: C. baranensis sp. nov., C. laevipennis sp. nov., C. urceolus sp. nov., and C. variistriatus sp. nov. from Guadalcanal and C. bougainvillensis sp. nov., and C. kietensis sp. nov. from Bougainville. Copelatus tulagicus Guignot, 1942, described from Tulaghi Island of the Solomons, is recorded from Guadalcanal and Santa Isabel for the first time. The widely distributed Australasian C. portior Guignot, 1956 is reported from the Solomon Islands (Guadalcanal and Ontong Java Atoll) for the first time. Two species from Guadalcanal remain unidentified since they are so far known only from a limited number of females.

Neoclypeodytes Young from Panama, with description of two new species (Coleoptera: Dytiscidae: Hydroporinae: Bidessini).

Minute Bidessini diving beetles of the genus Neoclypeodytes Young, 1967 from Panama are reviewed. Two new species, Neoclypeodytes balkei sp. nov. and N. fortunensis sp. nov. are described from Campana, Panama Province in central Panama, and La Fortuna, Chiriqui province in western Panama, respectively. Both species differ from all congeners by the colour pattern of the elytra and the shape of the male genitalia. Additionally, we provide a short diagnosis, illustrations and a new record for N. curtulus (Sharp, 1882). Furthermore, we report on the presence of scale-like setae at the apex of median lobe of the aedeagus of N. curtulus and N. fortunensis sp. nov., a character not previously observed in Neoclypeodytes species. With the addition of these two new species, there are now three species of Neoclypeodytes known from Panama and south of Guatemala.

A new Platambus from Sichuan, with new records of species of the P. sawadai group from China (Coleoptera: Dytiscidae: Agabinae).

Platambus binliui sp. nov. from Sichuan Province, China, is described and illustrated. It belongs to the P. sawadai species group sensu Nilsson (2000). The new species differs from other species of this group by the larger body, punctation of the dorsal surface and shape of male genitalia. New records of members of the P. sawadai group from China are provided: Platambus micropunctatus Nilsson, 2003 (Guangdong), P. punctatipennis Brancucci, 1984 (Fujian, Guangdong, Guizhou, Jiangxi, Zhejiang), P. regulae Brancucci, 1991 (Yunnan), representing a new species for Chinese fauna, and P. wangi Brancucci, 2006 (Hubei). Habitus and median lobe photographs for all mentioned species are provided.

Taxonomic revision of Australian Copelatus Erichson, 1832 (Coleoptera, Dytiscidae, Copelatinae).

The genus Copelatus in Australia is revised and nine species are recognised. One new species, Copelatus martinbaehri sp. nov., is described from Papua New Guinea (Central Province) and Cape York Peninsula (Iron Range NP and Mt Tozer). Copelatus divisus Watts, 1978, syn. nov., is considered a junior synonym of C. portior Guignot, 1956, described from New Guinea. Species delimitation is based on the morphological characters and Cox1 data. All species are (re)described, and their important species characters (median lobes, parameres, habitus and colour patterns) are illustrated. A key to all nine species is provided. The known distribution and habitat preferences of each species are outlined briefly. In Australia, all nine species are distributed in the northern half of the continent. Four species are also reported from New Guinea: in addition to C. martinbaehri sp. nov., we record C. clarki Sharp, 1882 for the first time from southern New Guinea, and consider literature records of C. irregularis W.J. Macleay, 1871 and C. marginatus Sharp, 1882 from New Guinea as doubtful. Copelatus portior is widely distributed in Australasia, while C. tenebrosus is widely distributed in the Indomalayan and Australasian realms. All Australian Copelatus are confirmed to be lentic, found in a large variety of stagnant water, mainly in lowland areas up to 250 m.

Annotated catalogue of beetles (Coleoptera) of the Socotra Archipelago.

Beetles of the Socotra Archipelago, Yemen, were catalogued. Altogether, 645 morphospecies from 56 families have been recognised from the Archipelago, of which 516 species (one with an additional two subspecies) were identified to the species level. Twenty-four, mostly widely distributed, species are recorded from the Socotra Archipelago for the first time, and three species are newly recorded for the islands Abd el Kuri (1) and Samha (2). Lithocharis socotrana Assing, 2015 (Staphylinidae), described from Socotra, is recorded from continental Yemen for the first time. Five incomplete or incorrect previous records are corrected. A total of 305 (47%) of all recorded species are considered to be endemic to the Socotra Archipelago. A total of 62 (10%) species are widely distributed Afrotropical species, and 35 (5.5%) East African species, often reaching also the Arabian Peninsula; 16 (2.5%) species occur in the eremial zone of Saharo-Arabian (or Saharo-Sindian) region. Only 14 (2%) species were previously known solely from the Arabian Peninsula; 30 (4.5%) species have cosmopolitan (and often anthropogenic) distributions; 28 (4.5%) species are widely distributed in (sub)tropical areas of the Old World; and 26 (4%) species have a predominantly western Palaearctic distribution. At present, 129 (20%) morphospecies remain unidentified; however, we expect that many of them represent as yet undescribed taxa endemic to the Archipelago.

Description of Neptosternus haibini sp. nov. from China (Coleoptera: Dytiscidae: Laccophilinae).

Neptosternus haibini sp. nov. is described from Guangdong Province, China. The new species is very similar to N. wewalkai Balke, Hendrich Yang, 1997, from which it can be recognised only by the shape of the male genitalia. The habitus and genitalia of both species are illustrated. Neptosternus pocsi Satô, 1972 is recorded from China (Yunnan province), and the Palaearctic region, for the first time. Currently, eight species of Neptosternus are known from China; a key to Chinese Neptosternus is provided.

Larvae of Huxelhydrus syntheticus Sharp, 1882 (Coleoptera: Dytiscidae: Bidessini).

The three larval instars of Huxelhydrus syntheticus Sharp, 1882, the only species of the New Zealand endemic genus Huxelhydrus Sharp, 1882, are described and illustrated including detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. Larvae of this species are characterized by the absence of the primary pore ABc, shared with all other known Bidessini larvae and therefore representing a potential synapomorphy of the tribe. Third instars of Huxelhydrus can be separated from those of all other known Bidessini genera by the following combination of characters: larger size, mandibular pore MNa located in a clearly distal position with respect to pore MNb, and presence of secondary setae on dorsal surface of protarsus, on posteroventral surface of all tarsi, and on urogomphus. First instars, on their part, can be distinguished by the presence of: an occipital suture, the primary pore PAk, a ventroapical spinula on antennomere 3, and an anterotransverse carina on meso- and metathorax.

Copelatus Erichson, 1832 from Maharashtra, India, with description of three new species and notes on other taxa of the genus (Coleoptera: Dytiscidae: Copelatinae).

The Copelatus species occurring in Maharashtra State, India, are reviewed. Altogether, nine species are recorded, three of which are described as new: Copelatus deccanensis sp. nov. (C. nigrolineatus species group), C. maushomi sp. nov. (C. consors group) and C. bezdeki sp. nov. (C. irinus group). Habitus and male genitalia are illustrated for all Copelatus species from Maharashtra, a key to the species and distribution maps are presented. New distributional records along with short diagnoses of already known species are provided. In addition, the study of extensive material of Copelatus species from the Indian subcontinent outside Maharashtra revealed the following new synonymies: Copelatus freudei Guignot, 1955 = C. gibsoni Vazirani, 1974 syn. nov. = C. gibsoni Vazirani, 1975 syn. nov. = C. spangleri Vazirani, 1974 syn. nov. = C. spangleri Vazirani, 1975 syn. nov.; Copelatus oblitus Sharp, 1882 = C. karnatakus Holmen Vazirani, 1990 syn. nov.; C. sociennus J. Balfour-Browne, 1952 = C. bangalorensis Vazirani, 1970 syn. nov.; Copelatus tenebrosus Régimbart, 1880 = C. ceylonicus Vazirani, 1969 syn. nov. = C. assamensis Vazirani, 1970 syn. nov.

Copelatus Erichson from the Dominican Republic, with the description of a new species, comments on elytral striation and faunistic notes on Antillean species (Coleoptera: Dytiscidae: Copelatinae).

The species of the genus Copelatus Erichson, 1832 occurring in the Dominican Republic are reviewed. Five species are recorded, with recent collecting data provided for four of them. Copelatus martini sp. nov., a member of the consors species group, is described and illustrated. It is compared to the apparently similar species C. guadelupensis Legros, 1948 based on morphological characters and on partial sequences of the CO1 gene. Interesting cases of intraspecific variability in the number of elytral dorsal striae in C. martini sp. nov. and C. vitraci are discussed in the light of the traditional taxo-nomic importance of this character for species group delimitation in Copelatus. Copelatus caelatipennis Aubé, 1838 and C. vitraci Legros, 1948 are recorded for the first time from the Dominican Republic (and therefore also from Hispaniola Island). The remaining species are C. posticatus (Fabricius, 1801), and C. insolitus Chevrolat, 1863 (for the latter, pre-sence in Hispaniola is doubtful and requires confirmation). Finally, C. guadelupensis is recorded from Puerto Rico for the first time, and a checklist of the Copelatus species of the Antilles is appended.

Two new species of Tenomerga Neboiss from eastern Asia (Coleoptera: Cupedidae).

Two new species of reticulated beetles (Cupedidae) are described: Tenomerga angulinota sp. nov. from Laos and T. helii sp. nov. from Sichuan, China. Important morphological characters of both new species are illustrated. T. angulinota sp. nov. can be easily recognized from all other Palaearctic-Oriental species by bifid anterior angles of pronotum; T. helii sp. nov. is in habitus very similar to widespread T. anguliscutis (Kolbe, 1886) and can be distinguished based on shape of pronotum, colour pattern of elytra and predominantly male genitalia. In addition, T. anguliscutis is for the first time recorded from Hainan and Jiangxi Provinces of China.