74 research outputs found
The new IMGC-02 transportable absolute gravimeter: measurement apparatus and applications in geophysics and volcanology
The research carried out at the Istituto Nazionale di Ricerca Metrologica (formerly Istituto di Metrologia ÂŤG.
ColonnettiÂť) aiming to develop a transportable ballistic absolute gravimeter ended with a new version of the instrument,
called the IMGC-02. It uses laser interferometry to measure the symmetrical free rising and falling
motion of a test mass in the gravity field. Providing the same accuracy achieved with previous versions, the instrumental
improvements mainly concern size, weight, data processing algorithms and operational simplicity.
An uncertainty of 9 ÎźGal (1 ÎźGal=1Ă10â8 m¡sâ2) can be achieved within a single observation session, lasting
about 12 h, while the time series of several observation sessions show a reproducibility of 4 ÎźGal. At this level,
gravity measurements provide useful information in Geophysics and Volcanology. A wide set of dynamic
phenomena, i.e. seismicity and volcanic activity, can produce temporal gravity changes, often quite small, with
an amplitude ranging from a few to hundreds of microgals. Therefore the IMGC absolute gravimeter has been
employed since 1986 in surveying the Italian active volcanoes. A brief history of the gravimeter and the description
of the new apparatus, together with the main results of ongoing applications in Geophysics and Volcanology
are presented
The new IMGC-02 transportable absolute gravimeter: measurement apparatus and applications in geophysics and volcanology
The research carried out at the Istituto Nazionale di Ricerca Metrologica (formerly Istituto di Metrologia ÂŤG.
ColonnettiÂť) aiming to develop a transportable ballistic absolute gravimeter ended with a new version of the instrument,
called the IMGC-02. It uses laser interferometry to measure the symmetrical free rising and falling
motion of a test mass in the gravity field. Providing the same accuracy achieved with previous versions, the instrumental
improvements mainly concern size, weight, data processing algorithms and operational simplicity.
An uncertainty of 9 ÎźGal (1 ÎźGal=1Ă10â8 m¡sâ2) can be achieved within a single observation session, lasting
about 12 h, while the time series of several observation sessions show a reproducibility of 4 ÎźGal. At this level,
gravity measurements provide useful information in Geophysics and Volcanology. A wide set of dynamic
phenomena, i.e. seismicity and volcanic activity, can produce temporal gravity changes, often quite small, with
an amplitude ranging from a few to hundreds of microgals. Therefore the IMGC absolute gravimeter has been
employed since 1986 in surveying the Italian active volcanoes. A brief history of the gravimeter and the description
of the new apparatus, together with the main results of ongoing applications in Geophysics and Volcanology
are presented
Side Chain Independent Recognition of Aminoacyl Adenylates by the Hint1 Transcription Suppressor
An Examination of Who Is Eligible and Who Is Receiving Bariatric Surgery in England: Secondary Analysis of the Health Survey for England Dataset (vol 29, pg 3246, 2019)
ENVIRONMENTAL MONITORING OF A SARDINIAN EARTHEN DWELLING DURING THE SUMMER SEASON
Abstract. Increasing interest in earth architecture has led to the development of new international
norms regarding these structures. Although Italy has no specific legislation for this
building type, both national laws for the safeguard of rural architecture and regional norms regarding
the conservation of historical centers have considerably slowed down the pace of their
destruction. This is particularly true for Sardinia, which maintains a conspicuous heritage of
âraw earthâ architecture, mostly in the old town centers of the Campidano plain and in its adjacent
valley. Due to the current legislation on energy efficiency in buildings, it has become essential
â particularly for the Sardinian region â to define guidelines for the improvement of energy
efficiency for this existing building heritage and identify the best parameters for their energetic
classification. Currently, these constructions are heavily penalized by the gap that persists
between the requirements of current energy balance evaluations, calculated upon heating
and domestic hot water energy demands, and the actual year-round energy performance, which
also includes the summer season. Moreover, this building type has a low lifecycle environmental
impact, but this aspect is not properly ârewardedâ by Italian regulations. The study proposed
herein firstly took into account the simulation of the thermal transient characteristics of
the adobe wall (brick made of clay, earth and straw, forged with wooden molds and sun dried).
Analytical calculations were performed using a transient model, assuming sinusoidal behavior
of all the parameters acting on the system. The results showed a high thermal inertia of the material
and a good ability in dampening the external thermal wave. Next, we conducted an internal
and external environmental monitoring of an existing earthen residential building in Sardinia
(âCasa Mancosuâ, Serramanna, VS), which provided the experimental data for the evaluation
of the whole building thermo-physical behavior. The measurements were taken during the
2010 summer season; the dwelling was not cooled by an air conditioning system. Thermal
comfort analyses based on these experimental data indicate that the roof is the âweakâ component,
creating local discomfort due to radiant asymmetry. The described methodology is expected
to be applicable also to the many buildings of this geographical area similar to the examined
one
L'accelerazione di gravitĂ in Metrologia, Geofisica e Geodesia: utilizzo e riferibilitĂ della misura
Lâinformazione che può essere derivata dalla conoscenza dellâaccelerazione dovuta al campo gravitazionale terrestre (convenzionalmente indicata con il simbolo g) è di fondamentale importanza in Metrologia ed in alcuni settori della Geofisica e della Geodesia.
Lâaccelerazione di gravità è spesso considerata una costante fisica. In realtĂ essa è una quantitĂ geofisica che varia rispetto alla posizione sulla Terra ed al tempo nello stesso luogo. Gli strumenti utilizzati nella sua determinazione sono i gravimetri assoluti e relativi. I primi forniscono una stima assoluta riferendosi ai campioni di lunghezza e di tempo. I secondi misurano una variazione riferendosi ad una differenza nota del campo gravitazionale.
In Metrologia il valore assoluto dellâaccelerazione di gravità è tradizionalmente utilizzato nella realizzazione dellâunitĂ di forza e di quelle unitĂ SI da essa derivate (coppia, durezza e pressione). Recentemente la stima di g ha anche assunto un ruolo importante nella determinazione delle costanti fondamentali, come la costante di Planck, su cui si basa una possibile ridefinizione del kilogrammo.
In Geofisica e Geodesia la conoscenza del campo gravitazionale fornisce informa-zioni sulla distribuzione delle masse e sulla densitĂ della crosta terrestre. La misura delle variazioni temporali di g è correlata a fenomeni geodinamici. Questi possono essere lenti e di piccola entitĂ oppure veloci ed intensi secondo la dinamicitĂ del sito di misura. Il monitoraggio del campo gravitazionale si basa su misure relative rispetto a stazioni di riferimento assolute, poste in una zona stabile in prossimitĂ dellâarea dinamica di interesse. La stabilitĂ delle stazioni di riferimento è verificata ripetendo periodicamente la misura assoluta di g.
Dal 2005 è operativo il nuovo gravimetro assoluto trasportabile IMGC-02, sviluppato nei laboratori dellâIstituto Nazionale di Ricerca Metrologica INRiM. LâIMGC-02 adotta il metodo balistico, riconosciuto come metodo primario per la misura dellâaccelerazione di gravitĂ . Il principio utilizzato è quello del moto simmetrico, in cui un grave è lanciato verso lâalto in una camera a vuoto acquisendone la traiettoria spazio-temporale con metodi ottico-interferometrici. Si utilizza uno schema derivato dallâinterferometro Michelson sostituendo i tradizionali specchi con retro-riflettori a spigolo di cubo. Uno dei due retro-riflettori è reso solidale alla massa pseudo-inerziale di un sismometro mentre lâaltro è direttamente soggetto al moto di caduta libera. Lâaccelerazione di gravità è ricavata minimizzando gli scarti tra le coordinate spazio-temporali del grave registrate durante lâesperimento ed unâequazione di modello del moto
Absolute Measurements of the Free-Fall acceleration g at the INRIM Force Laboratory
The work hereafter described was carried out on during the period April-May, 2006 by the Istituto Nazionale di Ricerca Metrologica (INRIM) of Turin (Italy).
The experimental results of absolute measurements of the free-fall acceleration carried out at the INRIM Force Laboratory are reported.
Gravity measurements were performed with the new transportable absolute gravimeter IMGC-02
Absolute measurements of the free fall acceleration g in Pantelleria (Italy)
The work hereafter described was carried out on June 23-36, 2007 by the Istituto Nazionale di Ricerca Metrologica (INRIM) for the Istituto Nazionale di Geofisica e Vulcanologia (INGV) - Centro Nazionale Terremoti and Osservatorio Vesuviano.
The experimental results of absolute measurements of the free-fall acceleration g carried out in Pantelleria are reported.
Gravity measurements were performed with the new transportable absolute gravimeter IMGC-02
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