Nedbrytning av organiskt material är en nyckelfaktor som påverkar omvandlingar av de många grundämnen som utgör eller är associerade till just organiskt material. En stor del av nedbrytningen av akvatiskt organiskt material (OM) sker i gränsskiktet mellan sediment och vatten. Eftersom så många biogeokemiska cykler styrs av nedbrytningen av OM är det viktigt att ha kunskap om processer och påverkansfaktorer både på mikro- och makronivå. Mineraliseringshastigheten av OM är en vanligt förekommande mätparameter, men vanligtvis inkluderar mätningarna inte de naturliga processer som kan påverka nedbrytnings-hastigheterna, t.ex. fysiska krafter. Syftet med den här studien är att studera mineraliseringshastigheten av det OM som finns naturligt i ytsediment i söt- och brackvatten när det utsätts för fysiska krafter som orsakar förändringar i redox-förhållanden, resuspension eller advektivt porvattenflöde. Fem laborativa experiment har utförts för att belysa syftet: Åldrat ytsediment från en sötvattens å utsattes för olika redox förhållanden där oxisk respiration, sulfatreduktion respektive metanogenes gynnades. Resultaten visade ingen skillnad i mineraliseringshastighet beroende på behandling. Detta motsäger studier utförda i marina miljöer, där anoxiska förhållanden ger en lägre mineraliseringshastighet än oxiska. Vidare gjordes två studier på brackvattensediment där effekten av resuspension var i centrum. Den ena studien fokuserade på frekvens och varaktighet av resuspensionstiderna, den andra på olika typer av sediment. Studierna visade att väldigt korta resuspensionstider med upp till 48 timmars stillhet mellan varje resuspension ökade mineraliseringstakten med fem gånger jämfört med diffusivt utbyte, och mer än dubblerades i jämförelse med kontinuerlig resuspension eller resuspension i långa perioder. Resuspensionen under kort tid var troligen gynnande då resuspension fysiskt stör bildningen av stabila bakteriesamhällen. Mineraliseringshastigheterna i sediment som domineras av väldigt fin, fin eller medium sand visade lika hastigheter, medan grov sand visade en signifikant lägre mineraliseringshastighet. Likheterna mellan de tre första sedimenttyperna kan dock ha påverkats av tillgång på lättnedbrytbart OM då sediment och vatten hämtades in under en algblomning. Till sist studerades effekten på mineraliseringshastigheten av advektivt porvattenflöde. Detta gjordes på åldrat sediment dels från en sötvattensbäck dels från en brackvattenstrand. Inget av de två sedimenttyperna visade någon skillnad i mineraliseringshastighet i jämförelse med diffusivt styrda system. Det är i motsats till tidigare marina studier, men är i linje med den första studien, där mineraliseringshastigheten var oberoende av redox-förhållande. Den generella slutsatsen från den här studien är nödvändigheten att studera samma aspekter i olika typer av akvatiska system, eftersom responsen verkar vara annorlunda beroende på system, t.ex. söt- brack- och saltvatten. Faktorer som kan förklara de här skillnaderna finns ännu inte, vilket gör att småskaliga studier och modeller blir viktiga verktyg för att utreda detta. / Organic matter mineralisation is a key parameter that affects most other element transformations associated with organic matter. A substantial part of aquatic organic matter (OM) mineralisation takes place at the interface between sediment and water. Understanding OM mineralisation is important at both the micro and macro scales, since it drives many biogeochemical cycles. OM mineralisation rates are widely measured, but generally not all the natural factors possibly affecting the rates, such as physical forcing, are considered. This thesis examines the mineralisation rates of indigenous OM in fresh and brackish surface sediments, subjected to different physical forces inducing changed redox conditions, resuspension, and advective pore water flow. Five experiments were performed to this end. Aged surface sediment from a freshwater river was subjected to different redox conditions favouring oxic respiration, sulphate reduction, and methanogenesis, respectively. Results indicated no difference in mineralisation rate irrespective of treatment. This contradicts what has been found in marine environments, where anoxic mineralisation rates are lower than oxic ones. Further, two studies of resuspension of brackish sediments were performed, one addressing the impact of the frequency and duration of the resuspension events, and the other addressing the impact of resuspension on different types of sediments. The studies found that very brief resuspension events followed by calm periods of up to 48 h increased mineralisation rates by five times compared to diffusion, and more than doubled the rate compared to continuous or long-term resuspension. The short-term events were possibly favoured because resuspension physically disturbs the arrangement of a stable bacteria community. Mineralisation rates on sediments dominated by very fine, fine, or medium-grained sand were the same, while coarse sand displayed a significantly lower rate. The similar rates of the three first sediment types could stem from access to labile OM, due to an ongoing algae bloom when the sediment and water samples were collected. Finally, the effect of advective pore water flow on aged sediment from one fresh and one brackish sediment was studied. Neither of the sediments displayed a mineralisation rate different from those occurring in incubations in which only diffusive exchange occurred. This contradicts the findings of previous marine studies, but is in line with the first study, which did not detect different mineralisation rates irrespective of redox conditions. The general conclusion is that it is necessary to study the same physical forces in different aquatic environments, since responses appear to differ, for example, between freshwater, brackish, and marine environments. Factors explaining these differences have not yet been expressed, making small-scale studies and modelling a challenge for future research.

Syftet med min undersökning var att bidra med ökade kunskaper om vilka uppfattningar som finns bland fjärdeklasselever gällande syftet med NTA i kemi, och om dessa överensstämmer med lärarens syfte. Datainsamlingen har gjorts via gruppintervjuer med femton elever och deras lärare. Intervjusvaren har sedan kategoriserats induktivt. Resultatet har visat att eleverna inte uppfattar syftet med NTA-lådan så som läraren tänkt. Det verkar som att eleverna ser ett mer närliggande syfte och fokuserar på vad som händer. Läraren, å andra sidan, tycks ha ett mer övergripande syfte som utgår från kunskapskraven men som hon inte fullt ut lyckas kommunicera till eleverna. Hon syftar även till att eleverna utvecklar sin resonemangsförmåga genom diskussioner i helklass. Eleverna tycker dessutom att helkassdiskussionerna är intressanta och lärorika. Tid läggs på diskussionerna vilket ger en möjlighet till en naturvetenskaplig literacitet. / The purpose of my study was to contribute with increased knowledge on what ideas fourth grade pupils have about the aims of NTA in chemistry, and if their ideas correspond with the teachers´ aims. The data collection is made through group interviews with fifteen pupils and their teacher. The answers in these interviews have been inductively categorized. The results have shown that pupils don´t see the aims of the NTA-boxes as the teacher have in mind. It seems like the pupils´ see aims in each lesson and focus on what is happening. The teacher, on the other hand, has a much more overall aim that originates from the curriculum, but which she doesn´t manage to fully communicate to the pupils. She also intends that the pupils should develop their capability of reasoning, which they do during classroom discussions. In addition to this, the pupils also find classroom discussions both interesting and educational. Time is given for classroom discussions which gives an opportunity for scientific literacy.

Human scent and human remains detection canines are used to locate living or deceased humans under many circumstances. Human scent canines locate individual humans on the basis of their unique scent profile, while human remains detection canines locate the general scent of decomposing human remains. Scent evidence is often collected by law enforcement agencies using a Scent Transfer Unit, a dynamic headspace concentration device. The goals of this research were to evaluate the STU-100 for the collection of human scent samples, and to apply this method to the collection of living and deceased human samples, and to the creation of canine training aids. The airflow rate and collection material used with the STU-100 were evaluated using a novel scent delivery method. Controlled Odor Mimic Permeation Systems were created containing representative standard compounds delivered at known rates, improving the reproducibility of optimization experiments. Flow rates and collection materials were compared. Higher air flow rates usually yielded significantly less total volatile compounds due to compound breakthrough through the collection material. Collection from polymer and cellulose-based materials demonstrated that the molecular backbone of the material is a factor in the trapping and releasing of compounds. The weave of the material also affects compound collection, as those materials with a tighter weave demonstrated enhanced collection efficiencies. Using the optimized method, volatiles were efficiently collected from living and deceased humans. Replicates of the living human samples showed good reproducibility; however, the odor profiles from individuals were not always distinguishable from one another. Analysis of the human remains samples revealed similarity in the type and ratio of compounds. Two types of prototype training aids were developed utilizing combinations of pure compounds as well as volatiles from actual human samples concentrated onto sorbents, which were subsequently used in field tests. The pseudo scent aids had moderate success in field tests, and the Odor pad aids had significant success. This research demonstrates that the STU-100 is a valuable tool for dog handlers and as a field instrument; however, modifications are warranted in order to improve its performance as a method for instrumental detection.

With increasing incidence rates aligned with poor prognosis; sepsis represents one of the biggest challenges in modern health care. It is a multifactorial syndrome defined as organ dysfunction caused by disturbed systemic response to an infection. Most of the inpatient sepsis are caused by Gram positive bacteria and one of its major constituents of the cell envelope: lipoteichoic acid (LTA). An adjuvant treatment that has gained prominence recently is extracorporeal blood removal therapies i.e., hemoperfusions. The concept is to remove the bacterial virulence factors that triggers immune responses and therefor stabilize the hemodynamic parameters of the patient. The dominating research of this method centres around adsorption of the Gram negative bacterias’ endotoxin lipopolysaccharide (LPS) but not LTA, whose biochemical and physiological properties resembles each other. The aim of this study was to determine whether LTA can be adsorbed using immobilized truncated derivates of antimicrobial peptides (AMPs). LTA was quantified using ELISA comparing before and after passage through columns with immobilized peptides. Further, the absorption abilities of LTA from two different solid phases with distinctive surfaces were investigated. This was of interest to elucidate the nature of the mechanisms behind LTA extractions. All results generated inconclusive data, except for one trial which demonstrated that peptide KEF-19 adsorbed most LTA and that the electrostatic force had the greatest influence of the adsorption. Future studies should however be carried out to validate these statements as well as feasibility and safety estimations for KEF-19 as the sorbent in hemoperfusions for Gram positive bacteria and LTA.

The disinfection of wastewater is not something that is currently in use at any wastewater treatmentplant in Sweden. The government has however stated some requirements for some wastewatertreatment plants to have a plan to implement disinfection in their treatment process, if asked.Therefore the goal of the project is to research if disinfection with sodium hypochlorite can beimplemented at Slottshagen wastewater treatment plant. There are several factors that will affect the efficacy of the disinfection of the wastewater. Firstly, thedisinfection process is dependent on the pH of the water solution. This is because the weakhypochlorous acid has better disinfection than the hypochlorite ion, and hypochlorous acid is presentthe most in the solution at pH 3-6. Another factor that is important to consider is the amounts ofnutrients present in the solution, since the chlorine oxidizes the nutrients rather than reacting with theorganisms in the solution. Some of the products from the oxidation of the nutrients are bad for bothhuman health and the environment. Also the temperature of the water and the concentration of thechlorine will affect the disinfection. Lastly, depending on which organism that is sought out to bedisinfected, the chlorine will have more or less effect on that particular organism. To research the chlorination effect, different additions of sodium hypochlorite were added to samplesolutions from the treatment plant and got to react in the solution for 5 minutes. Following thesamples were neutralized with ascorbic acid, and the amount of E. coli , coliform bacteria andintestinal enterococci were analyzed. The disinfection of the water during 1,5 minutes and at a shortertemperature were also analyzed. The results showed that the temperature, the contact time with thesolution and the concentration all are important factors to reach a proper disinfection, but the resultsalso showed that the amount of bacteria in the solution also is an aspect to take into considerationwhen treating wastewater. Finally, the considerations of disinfection of the wastewater with sodium hypochlorite is discussed.The point of addition of the chlorine was concluded to best be directly after the last chemicaltreatment step. When analysing if the disinfection would be possible, the disinfection was from theresults possible, but it was noticed that the results fluctuated a lot. The most probable reason why isbecause of the water quality. The water quality in general fluctuates regularly throughout the day, aswell as in between days of the week. Therefore throughout the disinfection process, the additions ofchlorine would need to be depending on several parameters, making the disinfection difficult toimplement. One solution to this could be to add a lot of chlorine to the bulk water at all times, but itwould cost too much if treating the water for a longer time, as well as it would be a higher risk to theenvironment. A solution to this problem could be to possibly neutralize the water before it is releasedas well, however when analyzing the cost of the ascorbic acid that was used as neutralization in thisproject, the cost to neutralize the water completely would be too high. Lastly it was discussed that theonly time disinfection of the wastewater would give any desirable results, is if the specific organismsthat are being sought out to be treated are bacteria or some viruses. If the particular organism that iswished to be treated is parasites, the disinfection with chlorine would not work.

Transport- och byggindustrin är en bidragande orsak till klimatkläget på grund av den betydande mängd växthusgaser som produceras. Att byta till elfordon är en metod för att minska de skadliga effekterna av klimatförändringarna. Under byggandet av nya vägar bidrar användningen av konventionella byggfordon som drivs av fossila bränslen till utsläppen av växthusgaser över hela världen. Följaktligen är behovet stort av att elektrifiera transport – samt konstruktionssekotorn. Som ett resultat har storleken på en potentiell mikronät som konstrueras med linjär optimering för att möta en statisk energiefterfrågan på en hypotetisk byggplats bedömts i denna studie. Det statiska energibehovet tillhandahölls från en fallstudie som syftade till att utvärdera en helt elektrifierad fordonsflotta för vägkonstruktionsindustrin.  Studien utgörs av två delar. Den första delen undersöker installationskapaciteterna för komponenterna i det potentiella mikronätet, medan den andra delen bedömer påverkan av den maximala anslutningskapaciteten till elnätet. En optimeringsmodell konstruerades genom att använda Python Optimization Modeling Objects (PYOMO). Antaganden och begränsningar för utformningen av mikronätet baseras på riktlinjer från Ramboll och Trafikverket.  Optimeringsmodellen gav en lösning som överensstämmer med energisystemets moderna kapacitet. Dock ansågs installationskapaciteterna för mikronätets komponenter vara opraktiska för den konceptuella byggplatsen. Metoden betonade behovet av verkliga data om belastningen som genereras av elektriska byggfordon (ECVs) samt data om anslutningen till elnätet. / The transportation and construction industry produces a sizable amount of greenhouse gases (GHGs), which significantly contribute to the worldwide problem of climate change. A strategy for reducing the adverse impacts of climate change on the environment is to switch to an electric vehicle fleet. The use of traditional construction vehicles powered by fossil fuels during road construction contributes to global GHG emissions. Consequently, electrification is required in this sector. As a result, the size of a potential microgrid constructed with linear optimization to meet a static energy demand of a hypothetical construction site is assessed in this thesis. The static energy demand was provided from a case study objected to evaluating a fully electrified construction vehicle fleet.  There are two parts to this thesis. The installation capacities of the potential microgrid's component parts are examined in the first section, and the impact of the maximum connection capacity to the electrical grid is assessed in the second. An optimization model was designed by utilizing Python Optimization Modeling Objects (PYOMO). Assumptions and delimitations considering the design of the microgrid are based on guidelines from Ramboll and the Swedish Transport Administration (STA).  The optimization model yielded a solution that aligns with state-of-the-art energy system capacities. However, the installation capacities of the microgrid components were found to be impractical for the conceptual construction site. The methodology stressed the need for real-world data on load generated by Electric Construction Vehicles (ECVs) and data regarding electrical grid connection.

Nanoparticles are used in many different applications because of their small size and unique properties. The usage is increasing rapidly, which will increase the nanoparticle exposure to the environment. Up till now, environmental behavior and ecotoxicology of nanoparticles have only been studied to a certain extent and because of the increasing usage, research should focus more on nanoparticle behavior and ecotoxicology. An effective way of studying nanoparticles in aqueous environments is to use mathematical models. In this study, the In vitro Sedimentation, Diffusion, and Dosimetry (ISDD) model was investigated and applied to copper, manganese, and zinc oxide nanoparticles to determine their sedimentation velocity in 1 mM NaClO4(aq).   The results show that the simulated sedimentation of nanoparticles in solution, i.e. the output from the ISDD model, can vary a lot depending on some of the input parameters in the model. The fact that some of these parameters have to be estimated increases the uncertainty of the ISDD model, although it is possible to yield results in great agreement with experimentally determined sedimentation velocities for the studied systems. The simulation results could always be explained by the theory behind it, which increases the reliability of the ISDD model.   The possibility of measuring the effective density of nanoparticle agglomerates using the volumetric centrifugation method was also investigated. This method makes it possible to avoid estimating the fractal dimension, an input parameter with great uncertainty in the ISDD model. The results look promising, although further investigation is needed.    The ISDD model seems to be a promising model for future simulation work. The model should be investigated further in order to minimize the uncertainties due to estimations. The possibility to predict nanoparticle sedimentation using a mathematical model will save a lot of time and money, and it can be a helpful tool in the extensive work of identifying the behavior of nanoparticles in aqueous environments.

As a direct consequence of the misuse of antibiotics since its first discovery, bacteria have developed extensive resistance mechanisms making them once again potential lethal threats. This eventuality has triggered a vast research effort from scientists worldwide to find solutions to mitigate antimicrobial resistance. One such option is the identification of new potential antimicrobial agents, like for example antimicrobial peptides (AMPs). Various methods have been applied to evaluate the properties and determine the complex mechanism of AMPs. However, the details of the mechanism remain unknown and hence the work in this project seeks to examine the suitability of using TIR Raman, a vibrational spectroscopy technique which is sufficiently surface sensitive to study the interaction of AMPs in contact with lipid bilayers, which are just a few nanometres thick. In order to evaluate the information that could be extracted from TIR Raman, measurement of solid supported lipid bilayers in the absence of peptides were first carried out. In particular, the lipid DMPC with a phase transition close to room temperature, was measured at various temperatures to determine spectral changes associated with the transition. For the peptide-membrane interactions, the AMP LL37 was put into contact with solid supported lipid bilayers modelling the cell membranes of bacteria (DOPE, DOPG) or humans (DOPC) respectively. The data clearly indicates that the membrane composition, and specifically the lipid head group charge, play an important role in the peptide-membrane interactions. In the bilayers mimicking bacteria cell membranes, the peptide either absorbed onto or inserted into the bilayer. In contrast, for the bilayer modelling a human cell membrane, no significant variations were detected, indicating no interaction with LL37. The findings presented in this work generally coincide with similar research of LL37 using other techniques. At hand of the herein presented data, TIR Raman has proven suitable and effective in detecting effects of antimicrobial peptides in contact with model lipid bilayers, and hence can be recommended for further studies. / Som en direkt följd av missbruket av antibiotika sedan det först upptäcktes, har bakterier utvecklat omfattande resistensmekanismer vilket föranlett dem att återigen utgöra potentiellt dödlig hot. Denna situation har manat fram en väsentlig forskningsinsats från forskare världen över att hitta lösningar för att minska antimikrobiell resistens. Ett sådant alternativ har varit identifieringen av nya potentiella antimikrobiella substanser, så som till exempel antimikrobiella peptider. Ett flertal metoder har använts för att både evaluera peptiders egenskaper och fastställa deras komplexa mekanism. Detta till trots förblir de exakta detaljerna i mekanismen okända, vilket föranlett arbetet i detta projekt att undersöka lämpligheten i att använda TIR Raman, en vibrational-spektroskopisk metod som är tillräckligt ytkänslig för att studera interaktionen hos antimikrobiella peptider i kontakt med lipidmembran, vilka endast är några få nanometer tjocka. För att evaluera informationen som kan utvinnas med TIR Raman, utfördes först mätningar av lipidmembran, skapade på ett solitt underlag, utan tillägg av peptider. Mer noggrant, har lipiden DMPC med en fasövergång nära vid rumstemperatur, mätts vid olika temperaturer för att fastställa spektrala variationer associerade till övergången. För peptid-membran interaktionerna, sattes den antimikrobiella peptiden LL37 i kontakt med lipidmembran som modellerar cellmembranet hos bakterier (DOPE, DOPG) respektive människor (DOPC). Mätdatan indikerar tydligt att membrankompositionen, och där specifikt laddningen av lipidens huvudgrupp, spelar en viktig roll i membran-peptid interaktionerna. För lipidmembranen som imiterar bakteriella cellmembran, adsorberade peptiden till membranet eller integrerades in i det. Till skillnad från detta, kunde inga signifikanta variationer detekteras för lipidmembranet som modellerade ett mänskligt membran vilket indikerar att det inte interagerar med peptiden LL37. Upptäckterna som presenteras i detta arbete sammanfaller generellt med andra, liknande studier där andra instrument använts för att undersöka LL37. Det kan ur materialet som presenterats här utläsas att TIR Raman visat sig lämpligt och effektivt i detekteringen av antimikrobiella peptider i kontakt med modeller av lipidmembran, och kan därav rekommenderas för fortsatta studier.

The industrial revolution came with its downside of emission of greenhouse gases into the atmosphere. The NOAA reported in 2019 that, of the greenhouse gases emitted into the atmosphere, CO2 contributed to about 80% of the increased greenhouse gases hence the need for CO2 Sequestering and Storage (CSS) and ultimately leading to Carbon Capture and Recycling (CCR) as a viable option to convert CO2 into useful forms. The race to find the best catalyst for CCR has led to the synthesis of many organometallic compounds. Pincer complexes catalyzed CO2 reduction has gained notoriety recently because of the tunability and robustness without causing any alteration in their overall coordination geometry. Different metals and pincer motifs have been reported for the electrocatalytic and photochemical reduction of CO2. Chapter I introduces the broader project impact, N-heterocyclic carbene concepts, pincer chemistry, iron pincer chemistry, and N-heterocyclic pincer complexes of Fe for a comprehensive perspective. Chapter II addresses the scarcity of iron based NHC pincer complexes due to deprotonation challenges and octahedral coordination preferences. Bulky substituents like mesityl, adamantly, or DIPP enable mono-ligated pincer complexes by hindering ligand encapsulation, leaving no open coordination site. In-situ metalation / transmetalation, and isolated CCC-NHC Zr complexes are presented along with a method to convert between mono-ligated and bis-ligated complexes. Chapter III explores L-type ligands' reactivity to prevent ligand reorganization around the Fe center from Chapter I. Chapter IV covers CCC-NHC Fe pincer complexes' synthesis, characterization, and transient absorption studies of bis-ligated complexes. Characterization of the CCC-NHC pincer Fe complexes in Chapter I-IV were carried out using 1H and 13C NMR spectroscopy, ESI-TOF MS, EA (Elemental Analysis), cyclic voltammetry, and X-ray diffraction. Chapter V discusses catalytic experiments and data consistent with preliminary CO2 reduction with mono-ligated CCC-NHC pincer complexes.

In this thesis H-bonded systems (natural gas hydrates, water clusters, and crystal ice) are studied by density functional theory (DFT) computations. Natural gas hydrates (NGHs) play an important role in energy and environmental fields: NGHs are considered as a promising backup energy resource in the near-future due to their tremendous carbon content; improper exploration of NGHs could induce geological disasters and aggravate the greenhouse effect. In addition, many technologies based on gas hydrates are being applied and developed. The thermodynamic stabilities of various water cavities in different clathrate crystalline phases occupied by hydrocarbon gas molecules are studied by dispersion-corrected hybrid functionals. The Raman spectra of C-C and C-H stretching vibrations of hydrocarbon molecules in various water cavities in the solid state are derived. The trends of C-H stretching vibrational frequencies are found to follow the prediction by the “loose cage ─| tight cage” model. In addition, the trends and origins of 13C NMR chemical shifts of hydrocarbon molecules in various NGHs are presented. These theoretical results will enlarge the database of C-C and C-H stretching vibrational frequencies and 13C NMR parameters of hydrocarbon molecules in NGHs, and provide valuable information to help identify the types of clathrate phases and varieties of guest molecules included in NGHs samples taken from natural sites. The behavior of water clusters may help to understand the properties of its liquid and solid states. The thermodynamic stabilities and IR spectra of a small-, medium-, and large-sized water cluster are studied in this work. After full optimization of (H2O)20,54,100 using the hybrid functional B3LYP, the electronic energies, zero-point energies, internal energies, enthalpies, entropies, and Gibbs free energies of the water clusters are computed. The OH stretching vibrational IR spectra of (H2O)20,54,100 are also presented and split into sub-spectra for different H-bond types based on the specific contributions from each group. It is found that the OH stretching vibrational frequencies of water are sensitive to the conformations of the H-bonds and the vibrations of the H-bonds belonging to different types are located in separated regions in the IR spectra. Thus, the spectroscopic fingerprints will reflect the H-bond topology of the water molecules in a water cluster. Ice XI has been suggested to be involved in the process of planetary formation as a considerable electric field might be formed from the ferroelectric ice XI in space. IR and Raman spectroscopic technology can be directly used to identify the occurrence of ferroelectric ice XI in laboratory or extraterrestrial settings. Due to the difficulty for DFT to describe non-covalent systems, the performance of 16 different DFT methods applied on the ice Ih, VIII, IX, and XI crystal phases are assessed. Based on the computational accuracy and cost, the IR and Raman spectra of ice Ih and XI are derived and compared. The librational vibrations are found to be the identifier which can be used to distinguish ice Ih and ice XI in the universe. In addition, the existence only one kind of H-bond in ice Ih is demonstrated from the overlapping sub-spectra for different types of H-bonded pair configurations in 16 isomers of ice Ih. The region of water under negative pressure is an exotic land in lack of exploitation. Guest free clathrate hydrate (clathrate ice) of sII type has been recently confirmed experimentally at negative pressure. Does any other clathrate ice phase exist at negative pressure region? Since clathrate hydrate are isostructural with silica clathrate minerals and semiconductor clathrates, and crystal structure prediction by analogy with known structures and first-principles computations is an effective way to find new crystalline phases of solid materials, we are motived to look for new clathrate ice phases from silica or semiconductor clathrate materials based on first-principles computations. Borrowing the idea new clathrate frameworks of ZnO and SiC can be constructed by connecting their bubble clusters in different ways, new clathrate ice phases (sL, sL_I, sL_II, and sL_III) are generated by connecting the water bubble clusters according to different rules. Using the non-local dispersion-corrected vdW-DF2 functional, clathrate ice sL with ultralow density (0.6 g/cm3) is predicted by first-principles phase diagram computations to be stable under larger negative pressures than the sII phase. The phase diagram of water is thus extended into the lower negative pressure region.