A method for designing robust multivariable feedback systems

A new methodology is developed for the synthesis of linear, time-invariant (LTI) controllers for multivariable LTI systems. The aim is to achieve stability and performance robustness of the feedback system in the presence of multiple unstructured uncertainty blocks; i.e., to satisfy a frequency-domain inequality in terms of the structured singular value. The design technique is referred to as the Causality Recovery Methodology (CRM). Starting with an initial (nominally) stabilizing compensator, the CRM produces a closed-loop system whose performance-robustness is at least as good as, and hopefully superior to, that of the original design. The robustness improvement is obtained by solving an infinite-dimensional, convex optimization program. A finite-dimensional implementation of the CRM was developed, and it was applied to a multivariate design example

Plant species from mesotrophic wetlands cause relatively high methane emissions from peat soil

Plants can influence methane emissions from wetland ecosystems by altering its production, consumption and transport in the soil. The aim of this study was to investigate how eight vascular plant species from mesotrophic to eutrophic wetlands vary in their influence on CH4 emissions from peat cores, under low and high N supply. Additionally, we measured the production of low-molecular-weight organic acids (LOA) by the same species (also at low and high N supply), because LOA form a substrate for methanogenesis. There were considerable differences among species in their effects upon rates of CH4 emission. Six of the species (Eriophorum latifolium Hoppe, Potentilla palustris (L.) Scop., Anthoxanthum odoratum (L.) s. str., Carex rostrata Stokes, Carex elata All., Carex acutiformis Ehrh.) increased CH4 emissions up to five times compared to control peat cores without plants, whereas two species (Phalaris arundinacea L., Phragmites australis (Cav.) Trin. ex Steud.) had no effect. There was a weak negative correlation between plant biomass and CH4 emission. N addition had no significant general effect upon CH4 emission. LOA production varied considerably among species, and tended to be highest for species from mesotrophic habitats. LOA production was stimulated by N addition. We conclude that some species from mesotrophic wetlands tend to cause higher CH4 emissions than species from eutrophic wetlands. This pattern, which contradicts what is often mentioned in literature, may be explained by the higher LOA production rates of species adapted to less productive habitat

"Klima-Isopren-Navigationssystem" - Ein Tool für human-biometeorologisch angepasste Routenführungen

Zur Erholung, der Bewegung und dem Aufenthalt im Freien werden besonders innerstädtische Grünflächen, aber auch Waldflächen von verschiedenen Bevölkerungsgruppen aufgesucht. Bei der Nutzung des Freiraums spielen bioklimatische und lufthygienische Faktoren eine wichtige Rolle. Während von der grünen Infrastruktur viele Vorteile ausgehen, können allerdings auch gesundheitliche Beeinträchtigungen durch sogenannte biologische Noxe entstehen. Ziel dieses Projektes ist es, möglichst lokalklimatisch, lufthygienisch und gesundheitlich optimierte Routen am Beispiel des Ozonbildungspotenzials auszuweisen. Um dies zu erreichen, soll eine Applikation programmiert werden, die initial als "Klima-Isopren-Navigationssystem" nutzbar ist und eine optimierte human-biometeorologische Routenführung für Nutzer aufzeigt, unabhängig vom Standort

Smarte Sirenen im Rahmen kommunaler Klimaanpassungskonzepte im Spannungsfeld von Stadtklimatologie und Stadtplanung

Der urbane Raum wird voraussichtlich besonders stark von Klimaveränderungen betroffen sein. Dies gilt es gegenwärtig zu berücksichtigen, um auf zukünftige Herausforderungen entsprechend vorbereitet und angepasst zu sein. Dabei gilt es vielfältige, oftmals widersprüchliche Anforderungen zu bewältigen, die mit unterschiedlichen Aspekten der Planung einhergehen. Mittels einer soliden und vorausschauenden Planung gilt es darauf Rücksicht zu nehmen, dass die Bevölkerung infolge von Stadtentwicklungs-, Stadterneuerungs- und Stadtumbaumaßnahmen in ihrer Wohn- und Lebensqualität nicht negativ beeinflusst wird (z. B. durch die Veränderungen des Lokalklimas, wenn Fußgänger im Sommer unnötigem Hitzestress ausgesetzt werden, da möglicherweise die vormals schattenspendende Vegetation einer Umstrukturierung zum Opfer gefallen ist). Eine der großen Herausforderungen der kommenden Jahre auf der Ebene der örtlichen Planung wird es sein, sich auf wetterbedingte Extreme wie Starkregenereignisse oder Hitzewellen vorzubereiten. Im Rahmen solcher rezenter Extremereignisse zeigt sich, dass die Folgen für die gesellschaftlichen und räumlichen Strukturen mitunter deutlich ausfallen können. Städte sind aber vielfach noch nicht ausreichend auf solche Szenarien vorbereitet. Auch wenn es gegenwärtig bereits eine große Anzahl an Klimaanpassungskonzepten gibt, ist die Klimaanpassung ein Arbeitsfeld, das weiterer Forschung bedarf, beispielweise hinsichtlich der Bewertung der Effektivität geplanter bzw. bereits umgesetzter Maßnahmen. Am Beispiel der knapp 100.000 Einwohner zählenden Stadt Kaiserslautern wird im Rahmen eines Forschungsprojektes ein Klimaanpassungskonzept entwickelt, das aufzeigt, wie die Siedlungs- und Freiraumentwicklung der Stadt klimaoptimiert auf Hitze- und Starkregenereignisse reagieren kann. Ein erster, wichtiger Baustein eines solchen Konzeptes ist eine zielführende stadtklimatologische/ siedlungsökologische Kartierung der Vor-Ort-Situation, um potentielle Risikogebiete für z. B. Starkregenereignisse im Bestand zu identifizieren. Darauf aufbauend sollen strategische Maßnahmenkonzepte für betroffene Quartiere erarbeitet werden. Als neues Konzept der Klimaanpassung soll dabei der Aufbau eines akustischen Warnsystems für die Bevölkerung untersucht und technisch ausgelegt werden. Extremereignisse mit Gefahrenpotential für die Bevölkerung, insbesondere Starkniederschläge, Gewitter und Stürme, erreichen die Städte oft mit sehr kurzer Vorwarnzeit. Nach dem weitgehenden Abbau der Zivilschutzsirenen bieten „smarte“ Sirenensysteme, die dezentral mit verhältnismäßig geringer Schallleistung installiert werden und situationsangepasste Sprachdurchsagen verteilen können, einen neuen Ansatz zur Schadenminimierung. Die Menschen sollen mithilfe eines optimierten Einsatzes von „Smarten Sirenen“ vor dem Eintreffen von Extremereignissen gewarnt werden, und dies unter Berücksichtigung der urbanen Gebäudestruktur, mit dem Ziel die betroffenen Standorte vorab zu informieren, um notwendige Maßnahmen, z. B. die Räumung von Tiefgaragen und Kellern, die Betätigung von Absperrventilen oder das Aufsuchen sicherer Orte, rechtzeitig treffen zu können

Cleaner Fish Do Not Impact the Pigmentation of Salmon Lice (Lepeophtheirus salmonis) in Commercial Aquaculture Cages

Salmon lice are one of the biggest challenges to sustainable salmonid aquaculture. The species display high evolutionary potential, which is evident by its development of resistance to numerous chemical compounds used for delousing. In response to this, salmon farms now use non-chemical delousing methods to minimize the damage done by salmon lice, including heavy reliance on cleaner fish. Anecdotal reports from farmers and fish health personnel in areas where cleaner fish are used have suggested that salmon lice are becoming less pigmented, potentially making them harder for cleaner fish to visually detect. This experiment investigated changes in the pigmentation of salmon lice in relation to the use of cleaner fish, louse stage and sex, temperature, preferred salmon swimming depth, daylength, and salinity. Salmon lice were sampled from snorkel cages on a commercial salmon farm where three cages were stocked with farmed lumpfish and ballan wrasse, and three cages were without cleaner fish. Water temperature, salinity, and depth were recorded using a conductivity, temperature, and depth recorder. Pigmentation was measured via photographic analysis of individual lice. Although louse pigmentation varied considerably throughout the experiment, using cleaner fish throughout a single production cycle did not reduce average louse pigmentation compared to control cages. On average, male lice were significantly darker pigmented than females, but otherwise there were no patterns in louse pigmentation in relation to life stage, salinity, temperature, or daylength. Salmon lice exhibit a high degree of evolvability and have become resistant to every chemical removal treatment developed thus far. The present data suggest that, with the densities and species of cleaner fish commonly used in commercial salmon production, there is not strong directional selection on louse pigmentation. Lice, at least with regard to visual appearance, are not likely to adapt in a way which reduces cleaner fish efficacy anytime soon.publishedVersio

Fiber Content and Viscosity of Seaweed Extract Eucheuma spinosum using Subcritical Water Method

This study was conducted to analyze the fiber content and viscosity of the Eucheuma spinosum seaweed. Seaweed, used in dry form, is extracted using subcritical water at 115°C and 125°C with time of 15, 20, and 25 minutes respectively using Hirayama HVE-50. The results of analysis of E.spinosum's fiber content and extract viscosity were obtained in the treatment of each of the lowest crude fibre levels in the 15 minute treatment at 115°C at 1.175%, and the highest at the 25 minute treatment at 125°C at 2.1525%. The analysis of insoluble fiber levels is lowest at 20 minutes of treatment at 125°C at 9.4% and the highest 20 minutes of treatment at 115°C at 16.64%. The analysis of dissolved dietary fiber is lowest at 15 minutes of treatment at 115°C at 2.21% and 25 minutes of treatment at 115°C at 12.61%. Viscosity analysis is lowest at 20 minutes with a temperature of 115°C at 22.465 cP and the highest time treatment at 115°C at 91.455 cP. Keywords: Eucheuma spinosum, fiber content, viscosity, and subcritical water Abstrak Penelitian ini dilakukan untuk menganalisis nilai kadar serat dan viskositas yang  terdapat pada rumput laut Eucheuma spinosum. Rumput laut yang digunakan dalam bentuk kering, diekstraksi menggunakan air subkritis pada suhu 115°C dan 125°C dengan waktu masing-masing selama 15, 20, dan 25 menit menggunakan autoclave tipe Hirayama HVE-50. Hasil analisis kadar serat dan viskositas ekstrak rumput laut E.spinosum diperoleh masing-masing pada perlakuan yaitu kadar serat kasar terendah terdapat pada perlakuan waktu 15 menit dengan suhu115°C sebesar 1,175%, dan tertinggi pada perlakuan waktu 25 menit dengan suhu 125°C sebesar 2,1525%. Analisis kadar serat pangan tak larut terendah pada perlakuan waktu 20 menit dengan suhu 125°C sebesar 9,4% dan tertinggi perlakuan waktu 20 menit dengan suhu 115°C sebesar 16,64%. Analisis serat pangan terlarut terendah pada perlakuan waktu 15 menit dengan suhu 115°C sebesar 2,21% dan tertinggi perlakuan waktu 25 menit dengan suhu 115°C sebesar 12,61%. Analisisviskositasterendah pada perlakuan 20 menitdengansuhu 115°C sebesar 22,465 cP dan tertinggi perlakuan waktu 25 menit dengan suhu 115°C sebesar 91,455cP. Kata Kunci: Eucheuma spinosum, kadar serat, viskositas, dan air subkriti

Secondary school student participation in carbon footprint assessment for schools

More and more cities are setting themselves ambitious climate protection targets, including CO2 neutrality. Schools are important institutions of cities and therefore they have to play a central role in achieving this goal. With the investment backlog building up and pressure from the Friday for Future movement increasing, the Wuppertal Institute and Büro Ö-quadrat have initiated the project Schools4Future, aiming to support secondary schools to become climate-neutral. In cooperation with secondary school students and teachers, the project team evaluated the existing situation of the participating schools and developed GHG-balances and feasible climate protection concepts. For this purpose, an Excel-based carbon footprint (CF) assessment tool for schools has been developed which is freely available. The tool covers all important emission areas, including heating energy, electricity use, travel to and from schools, school trips, the school canteen and paper consumption. The students were found capable to conduct the CF assessment with the guidance of the teacher, information materials and support of the researchers. So far, six pilot schools have completed their CF assessment with emissions ranging between 335 and 944 kg CO2 per person. In this paper we present the tool and compare the CF assessment of some schools. We further elaborate on how the tool and project has increased the climate awareness and self-efficacy of students and even stimulated measures by the school board

Comparing the mitochondrial signatures in ESCs and iPSCs and their neural derivations

Under embargo until: 2023-07-10Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) have distinct origins: ESCs are derived from pre-implanted embryos while iPSCs are reprogrammed somatic cells. Both have their own characteristics and lineage specificity, and both are valuable tools for studying human neurological development and disease. Thus far, few studies have analyzed how differences between stem cell types influence mitochondrial function and mitochondrial DNA (mtDNA) homeostasis during differentiation into neural and glial lineages. In this study, we compared mitochondrial function and mtDNA replication in human ESCs and iPSCs at three different stages − pluripotent, neural progenitor and astrocyte. We found that while ESCs and iPSCs have a similar mitochondrial signature, neural and astrocyte derivations manifested differences. At the neural stem cell (NSC) stage, iPSC-NSCs displayed decreased ATP production and a reduction in mitochondrial respiratory chain (MRC) complex IV expression compared to ESC-NSCs. IPSC-astrocytes showed increased mitochondrial activity including elevated ATP production, MRC complex IV expression, mtDNA copy number and mitochondrial biogenesis relative to those derived from ESCs. These findings show that while ESCs and iPSCs are similar at the pluripotent stage, differences in mitochondrial function may develop during differentiation and must be taken into account when extrapolating results from different cell types.acceptedVersio

Ekstraksi Kolagen Tulang Ikan Tuna (Thunnus sp) DENGAN ASAM KLORIDA

Previously, commercial collagen are obtained from mammals and poultry. However, there is a huge concern about Bovine Spongiform Encephalopathy (BSE, “mad cow disease”) and avian influenza from the consumers, that is why many researcher are trying to explore the utilization of marine animals as source of collagen. The aim of this study is to gathering information about extraction collagen from Tuna (Thunnus sp.) using 1% and 3% Chloride Acid. The result indicated that the rendement was 1,42 % and 5,65 %, moisture contents 7 % and 12 %, and acidity (pH) 4,30 % and 5,19 %. These results suggested that the using 3% chloride acid in the extraction process produced higher collagen. Sebelumnya, kolagen komersial diperoleh dari mamalia dan unggas. Namun demikian, terdapat kekhawatiran yang sangat besar terhadap Bovine Spongiform Encephalopathy (BSE, “penyakit sapi gila”) dan flu burung dari konsumen, oleh karena itu banyak peneliti yang mencoba untuk mengeksplorasi pemanfaatan hewan laut sebagai sumber kolagen. Tujuan dari penelitian ini adalah untuk memperoleh informasi tentang ekstraksi kolagen dari ikan tuna (Thunnus sp.) Menggunakan Asam Klorida 1% dan 3%. Hasil penelitian menunjukkan bahwa rendemen 1,42% dan 5,65%, kadar air 7% dan 12%, serta keasaman (pH) 4,30% dan 5,19%. Hasil ini menunjukkan bahwa penggunaan asam klorida 3% dalam proses ekstraksi menghasilkan kolagen yang lebih tinggi. 

Cemaran Mikrobiologi Pada Tepung Karagenan

The purpose of this study was to examine the microbiological contamination of carrageenan flour made by the steam method. In this study raw seaweed was used with 0.1%, 0.2%, 0.3% NaOH, and drying time. The results of this study obtained the highest yield at the concentration of NaOH 0.3% for 8 hours drying of the Sun that is equal to 19.48%. The lowest water content at the NaOH concentration of 0.3% increases in the drying time of the 12-hour drying cabinet which is 3.7%. Frequency pH stability 8.44 - 9.7. Research Results in The best total Plate Figures at a concentration of NaOH 0.3% for 8 hours of Sun Drying is 3000 colonies / g. The results of the study of Escherichia coli, Salmonella sp. Get negative results.Tujuan dari penelitian ini untuk mengetahui cemaran mikrobiologis pada tepung karagenan yang dibuat dengan metode uap. Pada penelitian ini digunakan perlakuan bahan baku rumput laut dengan dengan pelarut NaOH 0.1%, 0.2%, 0.3% dan lama pengeringan. Hasil penelitian ini diperoleh rendemen terbanyak pada konsentrasi NaOH 0.3% lama Pengeringan Matahari 8 jam yaitu sebesar 19.48%. Kadar air terendah pada konsentrasi NaOH 0.3% lama pengeringan Pengeringan Cabinet dryer 12 jam yaitu sebesar 3.7%. Stabilitas pH berkisar 8.44 – 9.7. Hasil Penelitian Angka Lempeng Total terbaik pada konsentrasi NaOH 0.3% dengan lama Pengeringan Matahari 8 jam yaitu sebesar 3000 koloni/g. Hasil penelitian Escherichia coli, Salmonella sp diperoleh hasil negatif.