Content: In most of the tanneries, water and chemicals are added manually in the tanning drum and pH of the float / leather is adjusted. Addition of correct amount of process recipe are necessary for better processing of the hides and minimizing wastage of utility, thereby controlling pollution load in effluent. However, fugitive-emission from process and drains accumulate ammonia, hydrogen-sulphide and volatile organic compounds which contribute bad odor in tannery as well as in wastewater-treatment premises causing problems to occupational health & safety of workers. Both local and supervisory control stations are employed to monitor and accurately manage the unit operations. The objective of this work is to produce consistent quality of leathers and to provide a healthy environment through automatic dosing and odor abatement system. Therefore the entire process control operation is integrated to operate through PLCs with following five modules: i) Water addition module ii) Chemical preparation and dosing system iii) pH monitoring and float recycle system iv) Drum rotation module v) Odor reduction module. In the integrated system, critical and bulk chemicals are stored in bulk storage tanks and are drawn into the load cell (LC) as per process sequence or recipe for feeding into the drums through auxiliary tanks. The float-recycle system helps to remix & heat the float where a pH electrode is housed to monitor pH online. The pH monitoring system adjusts addition of critical chemicals that indicates automatic end point. The contaminated air inside the tannery is sucked and passed through blower and then through bio-filter. The filtration process is based on the principle that VOCs (in the order of 50-200 ppm) and odors can be biologically treated by naturally occurring microbes. The control parameters monitored are: moisture in the bed and uniformity of media (contaminated air or process liquor). The humidity and temperature of inlet media is controlled and contact time with microbes is 10-30 secs. Moisture is controlled to maintain microbial population. A lead in laboratory scale has been developed to measure process variables (PV) considering their spatial distribution in two dimensions. Spatial distribution of process variables inside hides (across cross section) may provide accurate measurement of through reconstruction of image and data driven models using artificial intelligence tools. Computational intelligence is developed for updation of model parameters as that can be used for direct estimation of PV Take-Away: 1. Cleaner production is provided through automation of dosing & pH monitoring using PLC in indegeneous way 2. Pollution Load in exit stream and odor-gas emmision are minimized 3. Artificial Intelligence and data analytics techniques are used in Leather making

Content: Sheepskin, a by-product of the meat industry, is then often processed to leather, primarily for the clothing industry. Where the tanneries are distant from the abattoirs and freezing works, the raw skins have to be transported long distances to be processed. In warm weather, there is the potential for putrefaction of the skins which then have to be disposed of at a cost. Depilation, the first step of leather processing, is designed to remove the wool from the skin without damaging it. Conventional depilation involves the use of strong alkali and sulfides, that are harmful to both the environment and the personnel carrying out the process due to the potential production of hydrogen sulfide, a toxic, flammable gas. To solve this problem, scientists have been looking to depilate skins using enzymes as these are environmentally friendly. Various enzymes, such as collagenase, keratinase, protease and lipase have been shown to be able to remove hair from skin, but unfortunately usually damage it. Furthermore, at present, they are not cost effective at an industrial level. We have found a simple solution, a derivative of a dairy by-product, that prevents putrefaction, preserving the skin for days at room temperature. In addition, it allows easy removal of the wool from the skin. Scanning electron microscopy showed there was no obvious damage to the surface of the depilated skin and that the wool is cleanly removed from the hair follicle. To assess any less visible damage that may have occurred as a result of soaking the skin, biochemical analyses were carried out to measure the changes to the amino acid composition, collagen crosslinks and proteoglycan concentrations of the depilated skins. Sheepskin depilated with this method was processed to leather and its physical properties such as tear, and tensile strength analysed. Culture dependent methods were used to isolate the microorganisms present in the solution after depilation, showed that only four main species were consistently found in the depilation fluid and on the skins. Metagenomic analysis, confirmed these findings and was used to follow the changes in the microbiome during the course of depilation. This presentation will describe the progress that has been made to understand the science behind these observations and compare the properties of skins depilated using this method with those depilated using the traditional beamhouse process. Take-Away: We are using a natural product to depilate sheepskin. The sheepskin is also preserved while depilation. Microscopy, chemical analyses, physical tests, and metagenomics analysis were done to understand the process.

Content: The leather industry has been challenged to reduce its environmental impact, for example, by producing eco-friendly products with inherent biodegradability using less polluting chemicals. Conventional depilation of hair and wool consumes a large amount of lime and sodium sulphide, which poses a serious waste disposal concern. Volatile organosulphur compounds remaining in leather products may provoke an unpleasant odour and be the cause of a deterioration in indoor air quality. Traditional leather production also generates tanned waste which cannot be readily degraded by microorganisms. LASRA research is guiding the application of biotechnology to help the New Zealand leather industry develop environmentally sustainable leather processes, replacing hazardous chemicals with microbial enzymes. Using 16S rRNA gene sequencing, we have isolated and identified a number of indigenous bacteria from the leather industry environment which are being adopted to develop benign leather processing technologies. We discovered a strain of Stenotrophomonas spp. with significant and beneficial proteolytic activity in a tannery sludge. The identified strain not only displays collagenase activity but also the ability to reduce hexavalent chromium to trivalent chromium, making it an ideal candidate for biodegradation of tanned waste. We also isolated and identified several Bacillus spp. strains from a biofilter used in a leather manufacturing plant which exhibited sulphide oxidation activity, which are being applied in bioremediation of volatile organosulphur compounds emitted by leather products. Recently we revisited the natural autolytic processes of degradation of untreated pelts to guide a natural depilation method without any need for additional chemical treatment. The characterisation of the bacteria isolated from the skins showed the alkaline protease production activity responsible for the observed nature unhairing. We found that in controlled experiments the wool could be removed completely from follicles after 2 days, without obvious damage and leathers could be processed with organoleptic and mechanical properties comparable to conventionally processed counterparts. With the mechanisms revealed, the natural depilation can be controlled to become more reliable and reproducible across a range of conditions. Our current work is focused on the development of solid-state fermentation using skin and leather waste as a culture medium to produce the required enzymes to make biological leather production practical and reproducible. Our research is aimed at enabling the NZ leather industry to produce highquality leather products with a much-reduced environmental footprint. Take-Away: 1. Indigenous bacteria have been isolated and identified from the leather industry environment by the application of 16S rRNA gene sequencing. 2. Biodegradation of tanned waste and bioremediation of volatile organosulphur compounds are being developed. 3. The mechanism of natural depilation has been revealed and the application of enzymatic depilation can become practicable by using solid-state fermentation.

Content: “Red heat” is an industry term that describes the appearance of mostly red-pink coloured macroscopic microbial colonies on salt-cured hides and skins. Red heat-affected stock is undesirable as the resultant leather often shows obvious defects; but why this contamination is only superficial in other instances remains unclear. Previous work has focused on pigmented halophiles (‘salt-loving’ microbes) isolated from curing salts as the primary culprit. However, the identity of causative agents remains unspecified. Also, the involvement of non-pigmented microbes, and of microbes native to hides and skins, could be better understood. Thus, an investigation of the microbial communities that inhabit untreated bovine hide, curing salt, unaffected salt-cured bovine hide, and red heat-affected cured hide is proposed to uncover the microbial agents responsible for this contamination. This project aims to define these microbial communities using both a culture-dependent and –independent approach. Methods of microbe identification focus on marker gene amplification and sequencing. This is in contrast to earlier work which was restricted solely to phenotypic analyses. The 16S ribosomal RNA gene marker is used to identify members of Bacteria and Archaea, while the 18S and ITS2 regions of the fungal ribosomal RNA operon are targeted to detect fungi. Metagenomic amplicon sequencing using the Illumina MiSeq platform employs these same markers to determine taxonomic composition and relative abundance. Preliminary results from culturing identified different dominant species in curing salts screened for microbial growth. In agreement with earlier culture-based studies, these isolates were mostly pigmented, highly salt-tolerant members of the halophilic archaea of family Halobacteriaceae, as determined by marker gene sequencing. However, in agreement with more recent work within food preservation technology, nonpigmented isolates of halophilic archaea of genus Natrinema and bacterial genus Chromohalobacter were also found. It was also revealed that non-pigmented, quick-growing, salt-tolerant, proteolytic microbes were easily cultured from red heat-affected hide, most of the isolates were identified by marker gene sequencing as bacterial Pseudomonas halophila or Salicola. To determine red heat-causing microbes, future work involves the screening of isolates for extracellular enzyme activity; the most likely cause of red heat-associated damage. Sterile-salted hide samples will be inoculated with selected individual and combinations of isolates, and then further examined using confocal microscopy to check for reproducibility of red heat-associated damage. Take-Away: Different microbial species are found in different curing salts. Not all microbes involved in 'red heat' contamination are pigmented. The purpose is the possibility to overcome all the restrictions connected with the pin-wheel machine, the improvement of actual EN ISO methods of leather measurement and a better instrument to define tolerances considering the couple leather-machine.

Content: The shaving process is one of the most important steps in leather production. However, the underlying principles and mechanisms are not yet fully understood. Generally, the successful performance of the shaving process is based on long-time experience, and the tanneries rather optimize the preceding process steps than change the shaving parameters. In a current research project the research partners (Heusch GmbH, TU Dresden and FILK gGmbH) have united their expertise in order to understand the interaction between the shaving blade and the semi-finished leather (wet-blue or wet-white). The objective of the project is to gain more insight into the physics of shaving and to create a background of knowledge, which will be the technical base for developing novel and more effective shaving blades. Heusch presents the advantages of a novel serrated shaving blade. In comparison with the standard design an serrated blade yields higher shaving accuracy and uniform thickness of the hides. Stretching forces along the dorsal line of the hides are reduced, which avoids structural damage. Marginal hide regions are less frayed, thus increasing the usable surface area. The small size and compact form of the shavings are advantageous for recycling and disposal. Exploiting these advantages combined with an optimized grinding process, the user can increase the lifetime of the serrated blades. Based on these experiences there is an urgent need to thoroughly understand the physical cutting processes which take place during the shaving step. In the current research project an experimental test station is designed which is intended to simulate the shaving process in a simplified setting as a cutting procedure of a blade into a leather surface. This test station will enable the variation of material, geometry and configuration of the blade as well as the measurement of forces emerging during cutting at the blade and the leather surface, which emerge during cutting. The registered data shall provide information on the question, how the cutting forces depend on technological parameters, like blade material, geometry, configuration, cutting speed, leather moisture or tanning method. Based on the knowledge of these relationships novel, even more effective shaving blades can be developed. In a second approach the cutting process of a single leather fibre will be simulated virtually on a microscale level. The goal is the understanding of the interaction of a moving metal blade with a flexible, unilaterally fixed leather fibre. The simulation is supposed to yield data on cutting speed and fibre behaviour under conditions which are experimentally difficult to access. Take-Away: The physical basics of the shaving process are not yet fully understood. The presented research project aims at the understanding of the interaction between shaving blade and leather fibres during the shaving process. The approach in the project is to model the cutting procedure in a simplified experimental test station and in a computational simulation model.

In diesem Beitrag werden Berechnungsmodelle für Kurzschlussläufer-Asynchronmaschinen mit gestabtem Kupferkäfig und axial segmentierten Endringen vorgestellt. Die Auslegung des Käfigläufers erfolgt auf Basis eines analytischen Berechnungsansatzes, der die Anbindung zwischen Rotorstäben und Kurzschlussringen gemäß dem eingesetzten Laserschweißverfahren berücksichtigt. Als Vergleichsbasis für die Untersuchungen dienen Rotoren mit Aluminium- und Kupferkäfig, die mittels Druckgussverfahren hergestellt wurden. Anhand der Trennung der Verluste und der aus Leerlauf-, Belastungs- und Kurzschlussmessung ermittelten Ersatzschaltbildparameter werden die Einflüsse des Fertigungsverfahrens und Käfigmaterials auf Wirkungsgrad und Betriebsverhalten diskutiert. Darüber hinaus werden Aspekte zur mechanischen Drehzahlfestigkeit für Anwendungen in der Elektromobilität betrachtet. Mit dem Ziel der Erhöhung der Genauigkeit des Auslegungsprozesses werden numerische Berechnungsansätze zur möglichst exakten Berücksichtigung der Schweißverbindung im Kurzschlussring vorgestellt. / In this paper, calculation models for squirrel cage induction machines with a copper bar cage and axially segmented end rings are presented. For designing the squirrel cage winding, an analytical calculation approach has been developed, which takes into account the joining between rotor bars and end rings according to the laser welding process. As a basis of comparison rotors with aluminum and copper cage are considered, which have been manufactured by means of die casting process. Based on the separation of losses and the equivalent circuit parameters derived from no-load, load and short-circuit measurements, the effect of the manufacturing process and the cage material on the efficiency and the operating behavior are discussed. Furthermore, aspects of mechanical high-speed performance are presented for applications in electric mobility. Aiming on an increased accuracy of the design process, numerical calculation approaches taking into account the welding joint in the short-circuit ring are presented.

Dieser Beitrag gibt einen kurzen Überblick über das Patent als technisches Schutzrecht und seine Abgrenzung zu anderen gewerblichen Schutzrechten wie Gebrauchsmuster, Marke und Design. Weiterhin werden einige Anmelde- und Nutzungsstrategien für Patente skizziert. Der grundlegende Aufbau einer Patentanmeldung wird schließlich anhand des im Jahr 1889 von AEG angemeldeten Patents „Anker für Wechselstrommotoren“ erläutert, welches den Drehstrom-Asynchronmotor mit Kurzschlussläufer zum Gegenstand hat. / We provide a brief overview of patents as property rights for technical inventions as well as their distinction from other industrial property rights such as utility models, trademarks and designs. Furthermore, we outline some application and utilization strategies for patents. Finally, we explain the basic structure of a patent application by referring to the patent “Anker für Wechselstrommotoren” (armature for alternating current motors) filed by AEG in 1889 for protecting the three-phase asynchronous motor with squirrel cage rotor.

Der vorliegende Beitrag soll einen bewertenden Überblick über ausgewählte energieoptimale Regelungsstrategien für Asynchronmaschinen (ASM) geben . Diese werden zunächst in einer Simulationsumgebung implementiert und parametrisiert. Es erfolgt die Untersuchung beim Abfahren eines Fahrzyklus, sowie an einzelnen Lastpunkten. Die Resultate werden anhand ihrer Robustheit, der Praktikabilität des Regelverfahrens und nicht zuletzt am Energiesparpotential bewertet. Im ersten Teil wird die Struktur sowie Modellierung der zum Test der Regelungsalgorithmen verwendeten Komponenten vorgestellt. Auch werden die Regelungsstrategien an sich in Struktur und Funktion näher beleuchtet. Die Parametrisierung der entsprechenden Modelle erfolgt aus realen Prüfstandsdaten. Im zweiten Teil wird näher auf die zur späteren Bewertung verwendeten Verlustleistungsberechnung eingegangen. Der dritte Teil beschäftigt sich mit der Darstellung des zur Simulation verwendeten Lastzyklus. Zuletzt werden die Ergebnisse der Simulation vorgestellt und bewertet. / The present article is intended to provide an evaluative overview of four selected energy-optimized control strategies for asynchronous machines (ASM). These are first implemented and parameterized in a simulation environment. The investigation is carried out when running a driving cycle and at individual load points. The results are assessed on the basis of their robustness, practicability and, last but not least, their energy saving potential. In the first part, the structure and modeling of the components used to test the control algorithms is presented. The control strategies themselves are also examined in more detail in terms of structure and function. The corresponding models are parameterized from real test bench data. The second part deals in more detail with the power loss calculation used for the subsequent evaluation. The third deals with the representation of the load cycle used for the simulation. Finally, the results of the simulation are presented and evaluated.

Dieser Beitrag untersucht die Verluste elektrischer Maschinen in Abhängigkeit von der verwendeten Stromrichtertopologie und bei verschiedenen Pulsfrequenz. Beispielhaft wird eine permanentmagneterregte Synchronmaschine (PMSM) mit einer Bemessungsleistung von 18 kW behandelt. Zum Betrieb der Maschine wird der Prototyp des 3-Level-Stromrichters LT300-ML von M&P Motion Control and Power Electronics GmbH (M&P) verwendet. Beim 3-Level-Stromrichter werden mehr Spannungsebenen geschaltet als beim 2-Level-Stromrichter. Dies führt zu einer geringeren Stromwelligkeit und u. a. zu geringeren Verlusten in der Maschine. Die Messergebnisse zeigen, dass die Maschinenverluste im Vergleich zum Einsatz eines 2-Level-Stromrichters um 20 ... 30 % reduziert werden können. Für die Untersuchung wird der M&P-Maschinen-Prüfstand verwendet. / This paper deals with the losses of electrical machines depending on the converter topology used and with different switching frequency’s. A permanent magnet synchronous machine (PMSM) with a rated output power of 18 kW is investigated. As power converter the LT300-ML (3-level converter) from M&P Motion Control and Power Electronics GmbH (M&P) is used. By using a 3-level topology, more voltage levels are switched than with a 2-level topology. This, among other things, results in a lower current ripple and lower losses in the machine. The measurement results show that the machine losses can be reduced by 20 ... 30 % compared to the use of a 2-level converter. The M&P machine test bench is used for the investigation.

Der Beitrag stellt Zweischicht-Bruchlochwicklungen mit einem Wickelschritt von zwei Nuten als einen m¨oglichen Kompromiss vor, welcher weniger ohmsche Verluste als bei klassischen verteilten Wicklungen und weniger Ummagnetisierungsverluste als bei Zahnspulenwicklungen ermöglicht. Er diskutiert Entwurf und Eigenschaften solcher Wicklungen f¨ur drei- und sechssträngige Synchronmaschinen anhand ausgewählter Beispiele. / This paper presents two layer fractional slot windings with a winding step of two slots as a possible compromise which enables less ohmic loss than classic distributed windings would have and less hysteresis and eddy loss than fractional slot concentrated windings would have. It discusses properties and design of such windings for three- and six-phase synchronous machines based on selected examples.